Merge tag 'upstream/1.4.0'

Upstream version 1.4.0

102 files changed, 6350 insertions, 889 deletions

diff --git a/DESCRIPTION b/DESCRIPTION
index da8a548..b11e7fa 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,13 +1,13 @@
 Name: mapping
-Version: 1.2.1
-Date: 2016-02-06
+Version: 1.4.0
+Date: 2020-01-20
 Author: various authors
 Maintainer: Philip Nienhuis <prnienhuis@users.sf.net>
 Title: Mapping Functions
-Description: Simple mapping and GIS .shp and raster file functions.
+Description: Simple mapping and GIS .shp .dxf and raster file functions.
 Categories: Mathematics
-Depends: octave (>= 3.8.0)
-Suggested: io (>= 2.2.7), geometry (>= 1.4.0), octclip (>= 1.0.3), GDAL
+Depends: octave (>= 3.8.0), io (>= 2.2.7), geometry (>= 4.0.0)
+Suggested: GDAL
 Autoload: no
 License: GPLv3+
 Url: http://octave.sf.net
diff --git a/INDEX b/INDEX
index 579eab3..73e08fa 100644
--- a/INDEX
+++ b/INDEX
@@ -1,28 +1,76 @@
 mapping >> Mapping Functions
-Paths in curves
- azimuth
- distance
- reckon
-Lengths and angles
+Coordinate systems
+ aer2ecef
+ aer2enu
+ aer2geodetic
+ aer2ned
+ ecef2geodetic
+ enu2aer
+ enu2uvw
+ geocentricLatitude
+ geodetic2ecef
+ geodeticLatitudeFromGeocentric
+ geodeticLatitudeFromParametric
+ parametricLatitude
+ referenceEllipsoid
+ wgs84Ellipsoid
+DXF files
+ dxfdraw
+ dxfparse
+ dxfread
+GIS raster files
+ gdalread
+ rasterclip
+ rasterdraw
+ rasterinfo
+ rasterread
+GIS vector files
+ gmlread
+ isShapeMultipart
+ kmlread
+ kmzread
+ mapshow
+ geoshow
+ shapedraw
+ shapeinfo
+ shaperead
+ shapewrite
+GPS files
+ gpxread
+Lengths, angles and dimensions
+ axes2ecc
  deg2rad
+ deg2nm
+ deg2sm
  degtorad
  degrees2dm
  degrees2dms
  dm2degrees
  dms2degrees
+ earthRadius
+ ecc2flat
+ ecc2n
+ flat2ecc
  fromDegrees
  fromRadians
  km2deg
  km2rad
  km2nm
  km2sm
+ majaxis
+ meridianarc
+ minaxis
+ n2ecc
  nm2km
  nm2sm
  nm2rad
  nm2deg
  rad2deg
- radtodeg
  rad2km
+ rad2nm
+ rad2sm
+ radtodeg
+ rcurve
  sm2km
  sm2nm
  sm2rad
@@ -34,21 +82,16 @@ Lengths and angles
  wrapTo360
  wrapToPi
  wrapTo2Pi
+Paths in curves
+ azimuth
+ distance
+ reckon
 Utilities
+ closePolygonParts
  extractfield
+ makesymbolspec
+ polycut
  removeExtraNanSeparators
  roundn
+ utmzone
  validateLengthUnit
-Shape files
- mapshow
- geoshow
- makesymbolspec
- shapedraw
- shapeinfo
- shaperead
- shapewrite
-Raster files
- gdalread
- rasterdraw
- rasterinfo
- rasterread
diff --git a/NEWS b/NEWS
index fbdcdbc..16f68d4 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,93 @@
+Summary of important user-visible changes for mapping 1.4.0:
+-------------------------------------------------------------------
+
+ ** The mapping package now depends on the geometry and io packages. The
+    (suggested) dependency on the octclip package has been removed.
+
+ ** The following functions are new in mapping 1.4.0:
+
+      aer2ecef
+      aer2enu
+      aer2geodetic
+      aer2ned
+      axes2ecc
+      antipode
+      closePolygonParts
+      deg2nm
+      deg2sm
+      dxfdraw
+      dxfparse
+      dxfread
+      earthRadius
+      ecc2flat
+      ecc2n
+      ecef2geodetic
+      enu2aer
+      enu2uvw
+      flat2ecc
+      geodetic3ecef
+      geocentricLatitude
+      geodeticLatitudeFromGeocentric
+      geodeticLatitudeFromParametric
+      gmlread
+      gpxread
+      isShapeMultipart
+      kmlread
+      kmzread
+      majaxis
+      meridianarc
+      minaxis
+      n2ecc
+      parametricLatitude
+      polycut
+      rad2nm
+      rad2sm
+      rasterclip
+      rcurve
+      referenceEllipsoid
+      utmzone
+      wgs84Ellipsoid
+
+ ** Bug fixes:
+      shapedraw.m:  * Fix color arg. bug when drawing (poly)line
+                      geometries.
+                    * Restore input check order.
+                    * Do not connect multipoint shapes.
+      shaperead.m:  * Fix reading 'line' geometries.
+                    * Ignore shapes with (almost) infinite
+                      coordinates.
+                    * Fix .shx file usage.
+                    * Move file existence check to start of function.
+                    * Fix reading MultiPoint shapefiles.
+                    * Provision for absent M-values in M and Z
+                      shapetypes.
+                    * More robust input validation.
+                    * Properly process BoundingBox limits.
+                    * Fix incompatible dimensions bug when reading Multipoint files.
+                    * Fix reading selected attributes.
+      shapewrite.m: * Various fixes (credits to a.o., Martin Kunz, M.Parkan).
+                    * Properly write missing M-values.
+                    * Fix OOM error when writing large Point type files.
+                    * Fix and overhaul writing requested attributes.
+                    Fixes for bug #53422:
+                    * Unconditionally write .dbf file.
+                    * Fix record lengths for all Point types.
+                    * Fix XY coordinate write order for all Multipoint types.
+                    * Update .shx header as well.
+       rasterinfo.m: Show nr. of bands and bounding box.
+
+ ** Code improvements
+      shaperead.m:  * Invoke the Clipper library for clipping polylines
+                      and polygons, leading to much improved performance
+                      when invoking the BoundingBox option together with
+                      the Clip option. To use this feature the Octave-
+                      Forge geometry package >= 4.0.0 must be installed
+                      and loaded.
+
+ ** New features
+      shapewrite.m: * Allow writing M & Z shape types (Matlab-incompatible
+                      types, yet supported by Octave).
+
 Summary of important user-visible changes for mapping 1.2.1:
 -------------------------------------------------------------------
 
diff --git a/inst/aer2ecef.m b/inst/aer2ecef.m
new file mode 100644
index 0000000..97e9706
--- /dev/null
+++ b/inst/aer2ecef.m
@@ -0,0 +1,142 @@
+## Copyright (c) 2014-2020 Michael Hirsch, Ph.D.
+## Copyright (c) 2013-2020, Felipe Geremia Nievinski
+## Copyright (C) 2019-2020 Philip Nienhuis
+##
+## Redistribution and use in source and binary forms, with or without 
+## modification, are permitted provided that the following conditions are met:
+## 1. Redistributions of source code must retain the above copyright notice, 
+##    this list of conditions and the following disclaimer.
+## 2. Redistributions in binary form must reproduce the above copyright notice, 
+##    this list of conditions and the following disclaimer in the documentation 
+##    and/or other materials provided with the distribution.
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
+## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
+## THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+## ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
+## LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+## CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
+## SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
+## OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+## WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+## SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{x}, @var{y}, @var{z} =} aer2ecef (@var{az},@var{el}, @var{slantRange}, @var{lat0}, @var{lon0}, @var{alt0})
+## @deftypefnx {Function File} {@var{x}, @var{y}, @var{z} =} aer2ecef (@var{az},@var{el}, @var{slantRange}, @var{lat0}, @var{lon0}, @var{alt0}, @var{spheroid})
+## @deftypefnx {Function File} {@var{x}, @var{y}, @var{z} =} aer2ecef (@var{az},@var{el}, @var{slantRange}, @var{lat0}, @var{lon0}, @var{alt0}, @var{spheroid}, @var{angleUnit})
+## Convert azimuth, elevation, range to target from observer to ECEF coordinates.
+##
+## Inputs:
+##
+## @var{az}, @var{el}, @var{slantrange}: look angles and distance to point
+## under consideration (degrees, degrees, meters).  Vectors values are accepted
+## if they have equal dimensions.
+##
+## @var{lat0}, @var{lon0}, @var{alt0}: ellipsoid geodetic coordinates of
+## observer/reference (degrees, degrees, meters).  This must be just one
+## position.
+##
+## @var{spheroid}: referenceEllipsoid parameter struct; default is wgs84.  A
+## string value describing the spheroid is also accepted.
+## 
+## @var{angleUnit}: string for angular units ('degrees' or 'radians',
+## case-insensitive, just the first charachter will do). Default is 'degrees'.
+##
+## Outputs:
+## 
+## @var{x}, @var{y}, @var{z}: Earth Centered Earth Fixed (ECEF) coordinates.
+##
+## Example
+## @example
+## [x, y, z] = aer2ecef (33, 70, 1e3, 42, -82, 200)
+## x =    6.6057e+05
+## y =   -4.7002e+06
+## z =    4.2450e+06
+## @end example
+##
+## With radians
+## @example
+## [x, y, z] = aer2ecef (pi/6, pi/3, 1e3, pi/4, -pi/2, 200, "wgs84", "radians")
+## x =  250.00
+## y =   -4.5180e+06
+## z =    4.4884e+06
+## @end example
+##
+## Note: aer2ecef is a mere wrapper for functions geodetic2ecef, aer2enu and
+## enu2uvw.
+##
+## @seealso {geodetic2ecef, aer2enu, enu2uvw, referenceEllipsoid}
+## @end deftypefn
+
+## Function adapted from patch by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?8377
+
+function [x,y,z] = aer2ecef (az, el, slantrange, lat0, lon0, alt0, ...
+                             spheroid="", angleUnit="degrees")
+
+  if (nargin < 6)
+    print_usage();
+  endif  
+
+  if (! isnumeric (az)         || ! isreal (az) || ...
+      ! isnumeric (el)         || ! isreal (el) || ...
+      ! isnumeric (slantrange) || ! isreal (slantrange) ||...
+      ! isnumeric (lat0)       || ! isreal (lat0) || ...
+      ! isnumeric (lon0)       || ! isreal (lon0) ||  ...
+      ! isnumeric (alt0)       || ! isreal (alt0))
+    error ("aer2ecef.m: numeric values expected for first 6 inputs.");
+  endif
+
+  if (! all (size (az) == size (el)) || ...
+      ! all (size (el) == size (slantrange))) ...
+    error ("aer2ecef.m: non-matching dimensions of inputs.");
+  endif
+  if (! isscalar (lat0) || ! isscalar (lon0) || ! isscalar (alt0))
+    error ("aer2ecef: reference coordinates must be scalars.");
+  endif
+
+  if (isempty (spheroid))
+    E = wgs84Ellipsoid;
+  elseif (isstruct (spheroid))
+    E = spheroid;
+  elseif (ischar (spheroid))
+    E = referenceEllipsoid (spheroid);
+  endif 
+  
+  %% Origin of the local system in geocentric coordinates.
+  [x0, y0, z0] = geodetic2ecef (spheroid, lat0, lon0, alt0, angleUnit);
+  %% Convert Local Spherical AER to ENU
+  [e, n, u] = aer2enu (az, el, slantrange, angleUnit);
+  %% Rotating ENU to ECEF
+  [dx, dy, dz] = enu2uvw (e, n, u, lat0, lon0, angleUnit);
+  %% Origin + offset from origin equals position in ECEF
+  x = x0 + dx;
+  y = y0 + dy;
+  z = z0 + dz;
+
+endfunction
+
+%!test
+% [x2, y2, z2] = aer2ecef (33, 70, 1e3, 42, -82, 200);
+% assert ([x2, y2, z2], [660.930e3, -4701.424e3, 4246.579e3], 10e-6)
+% [x3, y3, z3] = aer2ecef ( 0.575958653158129, 1.22173047639603, 1e3, 0.733038285837618, -1.43116998663535, 200, "", "rad");
+% assert ([x3, y3, z3], [660.93019e3, -4701.42422e3, 4246.5796e3],10e-3)
+
+%!error <numeric> aer2ecef("s", 25, 1e3, 0, 0, 0)
+%!error <numeric> aer2ecef(3i, 25, 1e3, 0, 0, 0)
+%!error <numeric> aer2ecef(33, "s", 1e3, 0, 0, 0)
+%!error <numeric> aer2ecef(33, 3i, 1e3, 0, 0, 0)
+%!error <numeric> aer2ecef(33, 25, "s", 0, 0, 0)
+%!error <numeric> aer2ecef(33, 25, 3i, 0, 0, 0)
+%!error <numeric> aer2ecef(33, 25, 1e3, "s", 0, 0)
+%!error <numeric> aer2ecef(33, 25, 1e3, 3i, 0, 0)
+%!error <numeric> aer2ecef(33, 25, 1e3, 0, "s", 0)
+%!error <numeric> aer2ecef(33, 25, 1e3, 0, 3i, 0)
+%!error <numeric> aer2ecef(33, 25, 1e3, 0, 0, "s")
+%!error <numeric> aer2ecef(33, 25, 1e3, 0, 0, 3i)
+%!error <non-matching> aer2ecef ([1 1], [2 2]', [3 3], 4, 5, 6)
+%!error <non-matching> aer2ecef ([1 1], [2 2], [33], 4, 5, 6)
+%!error <reference> aer2ecef ([1 1], [2 2], [3 3], [4 4], 5, 6)
+%!error <reference> aer2ecef ([1 1], [2 2], [3 3], 4, [5 5], 6)
+%!error <reference> aer2ecef ([1 1], [2 2], [3 3], 4, 5, [6 6])
diff --git a/inst/aer2enu.m b/inst/aer2enu.m
new file mode 100644
index 0000000..3c60a86
--- /dev/null
+++ b/inst/aer2enu.m
@@ -0,0 +1,122 @@
+## Copyright (C) 2014-2020 Michael Hirsch
+## Copyright (C) 2013-2020 Felipe Geremia Nievinski
+## Copyright (C) 2019-2020 Philip Nienhuis
+##
+## Redistribution and use in source and binary forms, with or without modification, are permitted
+## provided that the following conditions are met:
+## 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+## 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer
+##    in the documentation and/or other materials provided with the distribution.
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
+## INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+## IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+## (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+## HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+## ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{e}, @var{n}, @var{u} =} aer2enu (@var{az}, @var{el}, @var{slantrange})
+## @deftypefnx {Function File} {@var{e}, @var{n}, @var{u} =} aer2enu (@var{az}, @var{el}, @var{slantrange}, @var{angleUnit})
+## Converts spherical azimuth, elevation and range coordinates into Cartesian
+## ENU coordinates.
+##
+## Inputs:
+## @itemize
+## @item
+## @var{az}, @var{el}, @var{slantrange}: look angles and distance to point
+## (degrees, degrees, meters).
+##
+## @item
+## @var{az}: azimuth angle clockwise from local north.
+##
+## @item
+## @var{el}: elevation angle above local horizon.
+##
+## @item
+## @var{slantrange}: distance from origin in local spherical system.
+##
+## @item
+## (Optional) angleUnit: string for angular units (radians or degrees).
+## Default is 'd': degrees
+## @end itemize
+##
+## Outputs:
+##
+## @itemize
+## @var{e}, @var{n}, @var{u}:  East, North, Up Cartesian coordinates
+## (meters).
+## @end itemize
+##
+## Example:
+## @example
+## [e, n, u] = aer2enu (33, 70, 1e3)
+## e =  186.28
+## n =  286.84
+## u =  939.69 
+## @end example
+##
+## In radians
+## @example
+## [e, n, u] = aer2enu (pi/4, pi/3,1e3, "radians")
+## e =  353.55
+## n =  353.55
+## u =  866.03
+## @end example
+##
+## @end deftypefn
+
+## Function adapted by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?8377
+
+function [e, n, u] = aer2enu (az, el, slantrange, angleUnit = "degrees")
+  
+  if (nargin < 3 || nargin > 4)
+    print_usage();
+  endif  
+
+  if (! isnumeric (az) || ! isreal (az) || ...
+      ! isnumeric (el) || ! isreal (el) || ...
+      ! isnumeric (slantrange) || ! isreal (slantrange))
+    error ("aer2enu.m : numeric input values expected");
+  endif
+
+  if (! all (size (az) == size (el)) || ! all (size (el) == size (slantrange)))
+    error ("aer2enu.m: non-matching dimensions of inputs.");
+  endif
+
+  if (! ischar (angleUnit))
+    error ("aer2enu.m: character value expected for 'angleUnit'");
+  elseif (strncmpi (angleUnit, "degrees", length (angleUnit)))
+    az = deg2rad (az);
+    el = deg2rad (el);
+  elseif (! strncmpi (angleUnit, "radians", length (angleUnit)))
+    error ("aer2enu.m: illegal input for 'angleUnit'");
+  endif    
+
+  ## Calculation of AER2ENU
+  u = slantrange .* sin (el);
+  r = slantrange .* cos (el);
+  e = r .* sin (az);
+  n = r .* cos (az);
+
+endfunction
+
+
+%!test
+%! [e, n, u] = aer2enu (33, 70, 1e3);
+%! assert ([e, n, u], [186.277521, 286.84222, 939.69262], 10e-6)
+%! [e, n, u] = aer2enu (0.57595865, 1.221730476, 1e3, "rad");
+%!  assert ([e, n, u], [186.277521, 286.84222, 939.69262], 10e-6)
+
+%!error <numeric> aer2enu("s", 25, 1e3)
+%!error <numeric> aer2enu(3i, 25, 1e3)
+%!error <numeric> aer2enu(33, "s", 1e3)
+%!error <numeric> aer2enu(33, 3i, 1e3)
+%!error <numeric> aer2enu(33, 25, "s")
+%!error <numeric> aer2enu(33, 25, 3i)
+%!error <non-matching> aer2enu ([1 1], [2 2]', [4 5])
+%!error <non-matching> aer2enu ([1 1], [2 2], [4 5 6])
+%!error <character> aer2enu (1, 2, 3, 4);
+%!error <Invalid call> aer2enu (1, 2)
+%!error <illegal> aer2enu (33, 70, 1e3, "f");
+%!error <illegal> aer2enu (33, 70, 1e3, "degreef");
diff --git a/inst/aer2geodetic.m b/inst/aer2geodetic.m
new file mode 100644
index 0000000..45f9b90
--- /dev/null
+++ b/inst/aer2geodetic.m
@@ -0,0 +1,128 @@
+## Copyright (c) 2014-2020 Michael Hirsch, Ph.D.
+## Copyright (c) 2013-2020, Felipe Geremia Nievinski
+## Copyright (C) 2019-2020 Philip Nienhuis
+##
+## Redistribution and use in source and binary forms, with or without 
+## modification, are permitted provided that the following conditions are met:
+## 1. Redistributions of source code must retain the above copyright notice, 
+##    this list of conditions and the following disclaimer.
+## 2. Redistributions in binary form must reproduce the above copyright notice, 
+##    this list of conditions and the following disclaimer in the documentation 
+##    and/or other materials provided with the distribution.
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
+## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
+## THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+## ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
+## LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+## CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
+## SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
+## OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+## WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+## SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{lat1}, @var{lon1}, @var{alt1} =} aer2geodetic (@var{az},@var{el}, @var{slantRange}, @var{lat0}, @var{lon0}, @var{alt0})
+## @deftypefnx {Function File} {@var{lat1}, @var{lon1}, @var{alt1} =} aer2geodetic (@var{az},@var{el}, @var{slantRange}, @var{lat0}, @var{lon0}, @var{alt0}, @var{spheroid})
+## @deftypefnx {Function File} {@var{lat1}, @var{lon1}, @var{alt1} =} aer2geodetic (@var{az},@var{el}, @var{slantRange}, @var{lat0}, @var{lon0}, @var{alt0}, @var{spheroid}, @var{angleUnit})
+## Convert azimuth, elevation and range of target from observer to geodetic
+## coordinates.
+## 
+## Inputs:
+##
+## @var{az}, @var{el}, @var{slantrange}: look angles and distance to point
+## under consideration (degrees, degrees, meters).  Vectors values are accepted
+## if they have equal dimensions.
+##
+## @var{lat0}, @var{lon0}, @var{alt0}: ellipsoid geodetic coordinates of
+## observer/reference (degrees, degrees, meters).  This must be just one
+## position.
+##
+## @var{spheroid}: referenceEllipsoid parameter struct or name (string value)
+## of referenceEllipsoid; default is 'wgs84'.
+## 
+## @var{angleUnit}: string for angular units ('degrees' or 'radians',
+## case-insensitive, just first character will suffice). Default is 'degrees'.
+##
+## Outputs:
+##
+## @var{lat1}, @var{lon1}, @var{alt1}: geodetic coordinates of points (degrees,
+## degrees, meters).
+##
+## Example
+## @example
+## [x, y, z] = aer2geodetic (33, 70, 1e3, 42, -82, 200)
+## x =  42.000
+## y = -82.000
+## z = 1139.7
+## @end example
+##
+## With radians
+## @example
+## [x, y, z] = aer2geodetic (pi/6, pi/3, 1e3, pi/4, -pi/2, 200, "wgs84", "radians")
+## x =  0.78547
+## y = -1.5707
+## z =  1066.0
+## @end example
+##
+## Note: aer2geodetic is a mere wrapper for functions aer2ecef followed by
+## ecef2geodetic.
+##
+## @seealso {aer2ecef, ecef2geodetic, referenceEllipsoid}
+## @end deftypefn
+
+## Function adapted by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?8377
+
+function [lat1, lon1, alt1] = aer2geodetic (az, el, slantrange, lat0, lon0, alt0, spheroid = "", angleUnit = "degrees")
+
+  if nargin < 6
+    print_usage();
+  endif  
+
+  if (! isnumeric (az)         || ! isreal (az) || ...
+      ! isnumeric (el)         || ! isreal (el) || ...
+      ! isnumeric (slantrange) || ! isreal (slantrange) || ...
+      ! isnumeric (lat0)       || ! isreal (lat0) || ...
+      ! isnumeric (lon0)       || ! isreal (lon0) ||  ...
+      ! isnumeric (alt0)       || ! isreal (alt0))
+    error ("aer2geodetic.m : numeric values expected for first six inputs.");
+  endif
+
+  if (isempty (spheroid))
+    E = wgs84Ellipsoid;
+  elseif (isstruct (spheroid))
+    E = spheroid;
+  elseif (ischar (spheroid))
+    E = referenceEllipsoid (spheroid);
+  else
+    error ("aer2geodetic: illegal value for 'spheroid'.");
+  endif 
+
+  [x, y, z] = aer2ecef (az, el, slantrange, lat0, lon0, alt0, spheroid, angleUnit);
+  [lat1, lon1, alt1] = ecef2geodetic (spheroid, x, y, z, angleUnit);
+
+endfunction
+
+%!test
+%! [lat2, lon2, alt2] = aer2geodetic (33, 70, 1e3, 42, -82, 200);
+%! assert ([lat2, lon2, alt2], [42.002581, -81.997752, 1.1397018e3], 10e-6);
+
+%!test
+%! [lat2, lon2, alt2] = aer2geodetic ( 0.575958653158129, 1.22173047639603, ...
+%!                      1e3, 0.733038285837618, -1.43116998663535, 200, "", "rad");
+%! assert ([lat2, lon2, alt2], [0.7330833, -1.4311307, 1.13970179e3], 10e-6)
+
+%!error <numeric> aer2geodetic ("s", 25, 1e3, 0, 0, 0)
+%!error <numeric> aer2geodetic (3i, 25, 1e3, 0, 0, 0)
+%!error <numeric> aer2geodetic (33, "s", 1e3, 0, 0, 0)
+%!error <numeric> aer2geodetic (33, 3i, 1e3, 0, 0, 0)
+%!error <numeric> aer2geodetic (33, 25, "s", 0, 0, 0)
+%!error <numeric> aer2geodetic (33, 25, 3i, 0, 0, 0)
+%!error <numeric> aer2geodetic (33, 25, 1e3, "s", 0, 0)
+%!error <numeric> aer2geodetic (33, 25, 1e3, 3i, 0, 0)
+%!error <numeric> aer2geodetic (33, 25, 1e3, 0, "s", 0)
+%!error <numeric> aer2geodetic (33, 25, 1e3, 0, 3i, 0)
+%!error <numeric> aer2geodetic (33, 25, 1e3, 0, 0, "s")
+%!error <numeric> aer2geodetic (33, 25, 1e3, 0, 0, 3i)
+%!error <illegal> aer2geodetic (33, 25, 1e3, 0, 0, 3, 5)
diff --git a/inst/aer2ned.m b/inst/aer2ned.m
new file mode 100644
index 0000000..8f65ceb
--- /dev/null
+++ b/inst/aer2ned.m
@@ -0,0 +1,112 @@
+## Copyright (c) 2014-2020 Michael Hirsch, Ph.D.
+## Copyright (c) 2013-2020, Felipe Geremia Nievinski
+## Copyright (C) 2019-2020 Philip Nienhuis
+##
+## Redistribution and use in source and binary forms, with or without 
+## modification, are permitted provided that the following conditions are met:
+## 1. Redistributions of source code must retain the above copyright notice, 
+##    this list of conditions and the following disclaimer.
+## 2. Redistributions in binary form must reproduce the above copyright notice, 
+##    this list of conditions and the following disclaimer in the documentation 
+##    and/or other materials provided with the distribution.
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
+## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
+## THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+## ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
+## LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+## CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
+## SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
+## OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+## WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+## SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{n}, @var{e}, @var{d} =} aer2ned (@var{az}, @var{el}, @var{slantrange})
+## @deftypefnx {Function File} {@var{n}, @var{e}, @var{d} =} aer2ned (@var{az}, @var{el}, @var{slantrange}, @var{angleUnit})
+## Convert azimuth, elevation and range to NED coordinates.
+##
+## Inputs:
+##
+## @var{az}, @var{el}, @var{slantrange}: look angles and distance to point
+## under consideration (degrees, degrees, meters).
+##
+## @var{angleUnit}: string for angular units ('degrees' or 'radians',
+## case-insensitive, lust the first character will do).  Default is 'degrees'.
+##
+## Outputs:
+##
+## @var{n}, @var{e}, @var{d}: North, East, Down coordinates of points.
+## (meters)
+##
+## Examples:
+## @example
+## [n, e, d] = aer2ned (33, 70, 1e3)
+## n =  286.84
+## e =  186.28
+## d = -939.69
+## @end example
+##
+## With radians
+## @example
+## [n, e, d] = aer2ned (pi/4, pi/3,1e3, "radians")
+## n =  353.55
+## e =  353.55
+## d = -866.03
+## @end example
+##
+## @end deftypefn
+
+## Function adapted by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?8377
+
+function [n, e, d] = aer2ned (az, el, slantrange, angleUnit = "degrees")
+  
+  if (nargin < 3)
+    print_usage();
+  endif  
+
+  if (! isnumeric (az)         || ! isreal (az) || ...
+      ! isnumeric (el)         || ! isreal (el) || ...
+      ! isnumeric (slantrange) || ! isreal (slantrange))
+    error ("aer2ned.m : numeric values expected for first three inputs.");
+  endif
+
+  if (! all (size (az) == size (el)) || ! all (size (el) == size (slantrange)))
+    error ("aer2ned.m: non-matching dimensions of inputs.");
+  endif
+
+  if (! ischar (angleUnit))
+    error ("aer2ned.m: character value expected for 'angleUnit'");
+  elseif (strncmpi (angleUnit, "degrees", length (angleUnit)))
+    az = deg2rad (az);
+    el = deg2rad (el);
+  elseif (! strncmpi (angleUnit, "radians", length (angleUnit)))
+    error ("aer2ned.m: illegal input for 'angleUnit'");
+  endif    
+
+   ## Calculation of AER2NED
+   d = -slantrange .* sin (el);
+   r = slantrange .* cos (el);
+   e = r .* sin (az);
+   n = r .* cos (az);
+
+endfunction
+
+%!test
+%! [n, e, d] = aer2ned (33, 70, 1e3);
+%! assert ([n, e, d], [286.84222, 186.277521, -939.69262], 10e-6)
+%! [e, n, u] = aer2ned (0.57595865, 1.221730476, 1e3, "rad");
+%! assert ([e, n, u], [286.84222, 186.277521, -939.69262], 10e-6)
+
+%!error <numeric> aer2ned("s", 25, 1e3)
+%!error <numeric> aer2ned(3i, 25, 1e3)
+%!error <numeric> aer2ned(33, "s", 1e3)
+%!error <numeric> aer2ned(33, 3i, 1e3)
+%!error <numeric> aer2ned(33, 25, "s")
+%!error <numeric> aer2ned(33, 25, 3i)
+%!error <non-matching> aer2ned ([1 1], [2 2]', [4 5])
+%!error <non-matching> aer2ned ([1 1], [2 2], [4 5 6])
+%!error <character> aer2ned (1, 2, 3, 4);
+%!error <illegal> aer2ned (33, 70, 1e3, "f");
+%!error <illegal> aer2ned (33, 70, 1e3, "degreef");
diff --git a/inst/antipode.m b/inst/antipode.m
new file mode 100644
index 0000000..1476693
--- /dev/null
+++ b/inst/antipode.m
@@ -0,0 +1,77 @@
+## Copyright (C) 2017-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {} {@var{lat_o, lon_o} =} antipode (@var{lat_i}, @var{lon_i})
+## @deftypefnx {} {@var{lat_o, lon_o} =} antipode (@var{lat_i}, @var{lon_i}, @var{unit})
+## Compute antipode (opposite point on globe).
+##
+## @var{lat_i} and @var{lon_i} (numeric values) are input latitude and
+## longitude, optionally vectors.
+##
+## Optional character argument @var{unit} (case-insensitive) can be one
+## of 'Degrees' or 'Radians' and can be used to specify the input
+## units.  Just 'd' or 'r' will do.
+##
+## @end deftypefn
+
+## Author: Philip Nienhuis <pr.nienhuis@users.sf.net>
+## Created: 2017-03-02
+
+function [lato, lono] = antipode (lati, loni, unit="")
+
+  if (nargin < 2 || nargout < 2)
+    print_usage ();
+  elseif (! isnumeric (lati) || ! isnumeric (loni))
+    error ("antipode: numeric arguments expected for latitude and longitude\n");
+  elseif (! ischar (unit))
+    error ("antipode: character argument expected for lat/lon unit\n");
+  elseif (nargin >= 3 && ! ismember (lower (unit(1)), {"d", "r"}))
+    error ("antipode: units must be one of 'Degrees' of 'Radians'");
+  endif
+
+  if (strncmpi (unit, "r", 1))
+    convfac = 180.0 / pi;
+    lati *= convfac;
+    loni *= convfac;
+  endif
+  lato = -abs (180.0 - wrapTo360 (lati - 90.0)) + 90.0;
+  lono = wrapTo180 (loni + 180);
+  if (strncmpi (unit, "r", 1))
+    lato /= convfac;
+    lono /= convfac;
+  endif
+
+endfunction
+
+%!test
+%! [lato, lono] = antipode (90, 0);
+%! assert ([lato, lono], [-90, 180], eps);
+
+%!test
+%! [lato, lono] = antipode (43, 15);
+%! assert ([lato, lono], [-43, -165], eps);
+
+%!test
+%! [lato, lono] = antipode ([-365; -360; -315; -270; -225; -185; -180; -135; -90; -45; 0; 45; 90; 135; 180; 225; 270; 315; 360], ...
+%!                          [-361; -359; -315; -270; -225; -185; -180; -135; -90; -45; 0; 45; 90; 135; 180; 225; 270; 315; 360]);
+%! assert ([lato, lono], [[5; 0; -45; -90; -45; -5; 0; 45; 90; 45; 0; -45; -90; -45; 0; 45; 90; 45; 0], ...
+%!        [179; -179; -135; -90; -45; -5; 0; 45; 90; 135; 180; -135; -90; -45; 0; 45; 90; 135; 180]], eps);
+
+%!error <numeric argument> [a, b] = antipode ("a", 1);
+%!error <Invalid call> a = antipode (0, 0);
+%!error <Invalid call> [a, b] = antipode (0);
+%!error <character argument expected> [a, b] = antipode (0, 0, 0);
+%!error <units must be one> [a, b] = antipode (0, 0, "a");
diff --git a/inst/axes2ecc.m b/inst/axes2ecc.m
new file mode 100644
index 0000000..aacda22
--- /dev/null
+++ b/inst/axes2ecc.m
@@ -0,0 +1,93 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} {@var{ecc} =} axes2ecc (@var{semimajor}, @var{semiminor})
+## @deftypefnx {Function File} {} {@var{ecc} =} axes2ecc (@var{axes})
+## Calculates the eccentricity from semimajor and semiminor axes.
+##
+## @var{semimajor} and @var{semiminor} are scalars or vectors of
+## semimajor and semiminor axes, resp.  Alternatively, they can also be
+## supplied as coordinate (row) vectors or a N2 matrix with each row
+## consisting of a (semimajor, semiminor) pair.
+##
+## Output arg @var{ecc} is a scalar or column vector of eccentricities.
+##
+## Examples:
+##
+## Scalar input:
+## @example
+##    format long
+##    axes2ecc (6378137, 6356752.314245)
+##    => 0.0818191908429654
+## @end example
+## 
+## Row vector (semimajor, semiminor):
+## @example
+##  axes2ecc ([6378137, 6356752.314245])
+##  =>  0.0818191908429654
+## @end example
+## 
+## Multivectors:
+## @example
+##    axes2ecc ([     71492, 66854; ...
+##                  6378137, 6356752.314245])
+##    ans =
+##       0.3543163789650412
+##       0.0818191908429654
+## @end example
+##               
+## @seealso(ecc2flat,flat2ecc)
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9492
+
+function ecc = axes2ecc (semimajor, semiminor=[])
+
+  if (nargin < 1)
+    print_usage ();
+
+  elseif (ischar (semimajor) || ischar (semiminor))
+    error ("axes2ecc: input args must be numeric");
+
+  elseif (nargin == 1)
+    s = size (semimajor);
+    if (s(2) != 2)
+      error ("axes2ecc: Nx2 matrix expected for arg. #1");
+    endif
+    ecc = sqrt ((semimajor(:, 1) .^ 2 .- semimajor(:, 2) .^ 2) ./ ...
+                (semimajor(:, 1) .^ 2));
+  else
+    ecc = sqrt ((semimajor .^ 2 .- semiminor .^ 2) ./ (semimajor .^ 2));
+  endif
+
+endfunction
+
+
+%!test
+%! semimajor = 6378137;
+%! semiminor = 6356752.314245;
+%! Earth = [ semimajor, semiminor ];
+%! Jupiter = [ 71492 , 66854 ];
+%! Planets = [ Jupiter ; Earth ];
+%! assert (axes2ecc (semimajor, semiminor), 0.0818191908429654, 10e-12);
+%! assert (axes2ecc (Earth), 0.0818191908429654, 10e-12);
+%! assert (axes2ecc (Planets), [ 0.354316379; 0.081819190843 ], 10e-10);
+%! assert (axes2ecc (Planets(:, 1), Planets(:, 2)), [ 0.354316379; 0.081819190843 ], 10e-10);
+
+%!error <must be numeric> axes2ecc ("a", 1);
+%!error <Nx2 matrix expected> axes2ecc ([1; 2]);
diff --git a/inst/azimuth.m b/inst/azimuth.m
index cbb24bd..698e0fd 100644
--- a/inst/azimuth.m
+++ b/inst/azimuth.m
@@ -1,5 +1,5 @@
-## Copyright (C) 2004 Andrew Collier <abcollier@users.sourceforge.net>
-## Copyright (C) 2006 Alexander Barth <abarth93@users.sourceforge.net>
+## Copyright (C) 2004-2020 Andrew Collier <abcollier@users.sourceforge.net>
+## Copyright (C) 2006-2020 Alexander Barth <abarth93@users.sourceforge.net>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
diff --git a/inst/closePolygonParts.m b/inst/closePolygonParts.m
new file mode 100644
index 0000000..9a60863
--- /dev/null
+++ b/inst/closePolygonParts.m
@@ -0,0 +1,152 @@
+## Copyright (C) 2017-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File}  [@var{Xo}, @var{Yo}, ... ] = closePolygonParts (@var{Xi}, @var{Yi}, ...)
+## @deftypefnx {Function File} [@var{Xo}, @var{Yo}, ... ] = closePolygonParts (@var{Xi}, @var{Yi}, ..., @var{angunit})
+## Ensure that (each part of a multipart) polygon is a closed ring.
+##
+## For each (part of a) polygon, closePolygonParts checks if the vertices
+## of that part form a closed ring, i.e., if first and last vertices coincide.
+## If the polygon or polygon parts (the latter separated separated by NaNs) do
+## not form a closed ring, the first vertex coordinates of each open part are
+## appended after its last vertex.  Input polygons need not be multipart.
+##
+## @var{Xi} and @var{Yi} (plus optionally, @var{Zi} and/or @var{Mi}) are input
+## vectors of X and Y or Longitude and Latitude (plus optionally Z or Height,
+## and/or M) vectors of vertex coordinates (and measure values) of an input
+## polygon.  If a vector of measures is given as argument, it should always be
+## the last vector.
+##
+## Optional last argument @var{angunit} can be one of 'Degrees' or 'Radians'
+## (case-insensitive, only the first 3 characters need to match).  If this
+## argument is given and if the first two input vectors are longitude/latitude
+## vectors rather than X/Y vectors, it indicates that the longitudes of those
+## first and last vectors need only coincide modulo 360 degrees or 2*pi radians.
+##
+## The number of output vectors @var{Xo}, @var{Yo}, ... matches the number of
+## input vectors.
+##
+## @seealso{isShapeMultiPart}
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2017-11-08
+
+function [varargout] = closePolygonParts (varargin)
+
+  nargs = nargin;
+  ang = 0;
+  ## Input checks
+  if (ischar (varargin{end}))
+    ang = find (ismember ({"rad", "deg"}, lower (varargin{end}(1:3))));
+    if (isempty (ang))
+      error ("closePolygonParts: unknown angle unit: '%s'; must be Degrees or Radians", ...
+              varargin{end});
+    endif
+    --nargs;
+  endif
+  if (! all (cellfun (@isnumeric, varargin(1:nargs))))
+    error ("closePolygonParts: numeric input vectors expected");
+  elseif (nargs != nargout)
+    error ("closePolygonParts: nr. of input vectors doesn't match nr. of output vectors");
+  endif
+  ## Check orientation, matching NaN positions and lengths of input vectors
+  mp = cell (nargs, 1);
+  for ii=1:nargs
+    mp(ii) = find (isnan (varargin{ii}));
+  endfor
+  for ii=2:nargs
+    if (numel (varargin{ii-1}) != numel (varargin{ii}))
+      error ("closePolygonParts: incompatible input vectors #%d and #%d", ii-1, ii);
+    endif
+    if (isrow (varargin{ii-1}) != isrow (varargin{ii}))
+      error ("closePolygonParts: all input vectors should have same dimension");
+    endif
+    ## Check NaN positions. M vectors may have more NaNs indicating missing values
+    if (! isempty (mp{ii-1}) && ! isempty (mp{ii}) && ...
+        numel (mp{ii-1}) == numel (mp{ii}))
+      ## The next loop uses ismember() to cope with M vectors with missing values
+      if (! all (ismember (mp{ii-1}, mp{ii})))
+        error ("closePolygonParts: NaN positions of arg# %d and arg #d don't match", ii-1, ii);
+      endif
+    endif
+  endfor
+
+  ## Input validation done, check for open rings.
+  ## Assess extent of each polygon part.
+  idn = [ 0 (find (isnan (varargin{1}))) (numel (varargin{1})+1) ];
+  ## Process polygons backwards to avoid stale (multipart) idn indices
+  for jj=numel (idn)-1 : -1 : 1
+    isclosed = true;
+    if (ang == 1)
+      isclosed = isclosed && ...
+                 abs (wrapTo2Pi (varargin{1}(idn(jj)+1)) - wrapTo2Pi (varargin{1}(idn(jj+1)-1))) < eps;
+    elseif (ang == 2)
+      isclosed = isclosed && ...
+                 abs (wrapTo360 (varargin{1}(idn(jj)+1)) - wrapTo360 (varargin{1}(idn(jj+1)-1))) < eps;
+    else
+      isclosed = isclosed && ...
+                 abs (varargin{1}(idn(jj)+1) - varargin{1}(idn(jj+1)-1)) < eps;
+    endif
+    for ii=2:nargs
+      isclosed = isclosed && ...
+                 abs (varargin{ii}(idn(jj)+1) - varargin{ii}(idn(jj+1)-1)) < eps;
+    endfor
+    if (! isclosed)
+      for ii=1:nargs
+        varargin{ii}(idn(jj+1):end+1) = varargin{ii}(idn(jj+1)-1:end);
+        varargin{ii}(idn(jj+1)) = varargin{ii}(idn(jj)+1);
+      endfor
+    endif
+  endfor
+
+  for ii=1:nargs
+    varargout{ii} = varargin{ii};
+  endfor
+
+endfunction
+
+
+%!test
+%! xi = [ 1 5   6  2 NaN  11 15 16 12 ];
+%! yi = [ 1 2   5  6 NaN   1  2  5  6 ];
+%! zi = [ 1 3   5  3 NaN  11 13 15 13 ];
+%! mi = [ 8 9 NaN -1 NaN NaN -3 -2 NaN];
+%! [a, b, c, d] = closePolygonParts (xi, yi, zi, mi);
+%! assert (a, [1 5 6 2 1 NaN 11 15 16 12 11], 1e-10);
+%! assert (b, [1 2 5 6 1 NaN  1  2  5  6  1], 1e-10);
+%! assert (c, [1 3 5 3 1 NaN 11 13 15 13 11], 1e-10);
+%! [d, e, f] = closePolygonParts (a, b, c);
+%! assert (a, d, 1e-10);
+%! assert (b, e, 1e-10);
+%! assert (c, f, 1e-10);
+
+%!test
+%! xxi = [ 400 405 406 402 NaN 311 315 316 312 671 ];
+%! yyi = [   1   2   5   6 NaN   1   2   5   6   1 ];
+%! zzi = [   1   3   5   3 NaN  11  13  15  13  11 ];
+%! [a, b, c] = closePolygonParts (xxi, yyi, zzi, "deg");
+%! assert (a, [400 405 406 402 400 NaN 311 315 316 312 671], 1e-10);
+%! assert (b, [  1   2   5   6   1 NaN   1   2   5   6   1], 1e-10);
+%! assert (c, [  1   3   5   3   1 NaN  11  13  15  13  11], 1e-10);
+
+%!error <unknown angle unit> a = closePolygonParts ([0 1], "ged");
+%!error <numeric input vectors expected> [a, b] = closePolygonParts ([0 1], {"c", "d"})
+%!error <nr. of input vectors> a = closePolygonParts ([0 1], [2 3])
+%!error <nr. of input vectors> a = closePolygonParts ("radians")
+%!error <incompatible input vectors> [a, b] = closePolygonParts ([0 NaN 1], [2 NaN 3 4])
+%!error <NaN positions of> [a, b] = closePolygonParts ([0 1 NaN 1], [2 NaN 3 4])
diff --git a/inst/deg2km.m b/inst/deg2km.m
index 4b687b9..d50d6f5 100644
--- a/inst/deg2km.m
+++ b/inst/deg2km.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2013 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2013-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
@@ -27,7 +27,8 @@
 ## "moon", "mars", "jupiter", "saturn", "uranus", "neptune", or "pluto", in
 ## which case radius will be set to that object mean radius.
 ##
-## @seealso{km2deg}
+## @seealso{deg2km, deg2sm, km2rad, km2deg,
+## nm2deg, nm2rad, rad2km, rad2nm, rad2sm, sm2deg, sm2rad}
 ## @end deftypefn
 
 ## Author: Alexander Barth <barth.alexander@gmail.com>
diff --git a/inst/deg2nm.m b/inst/deg2nm.m
new file mode 100644
index 0000000..728d266
--- /dev/null
+++ b/inst/deg2nm.m
@@ -0,0 +1,62 @@
+## Copyright (C) 2013-2020 Alexander Barth
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+##
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+##
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{nm} =} deg2nm (@var{deg})
+## @deftypefnx {Function File} {@var{nm} =} deg2nm (@var{deg}, @var{radius})
+## @deftypefnx {Function File} {@var{nm} =} deg2nm (@var{deg}, @var{sphere})
+## Converts angle in degrees to distance in nautical miles by multiplying angle
+## with radius.
+##
+## Calculates the distances @var{nm} in a sphere with @var{radius} (also in
+## nautical miles) for the angles @var{deg}.  If unspecified, radius defaults to
+## 3440 nm, the mean radius of Earth.
+##
+## Alternatively, @var{sphere} can be one of "sun", "mercury", "venus", "earth",
+## "moon", "mars", "jupiter", "saturn", "uranus", "neptune", or "pluto", in
+## which case radius will be set to that object's mean radius.
+##
+## @seealso{deg2km, deg2sm, km2rad, km2deg,
+## nm2deg, nm2rad, rad2km, rad2nm, rad2sm, sm2deg, sm2rad}
+## @end deftypefn
+
+## Built with insight from
+## Author: Alexander Barth <barth.alexander@gmail.com>
+## Adapted from deg2km.m by Anonymous contributor, see patch #9709
+
+function nm = deg2nm (deg, radius="earth")
+
+  ## Check arguments
+  if (nargin < 1 || nargin > 2)
+    print_usage();
+  elseif (ischar (radius))
+    ## Get radius of sphere with its default units (km)
+    radius = km2nm (spheres_radius (radius));
+  ## Check input
+  elseif (! isnumeric (radius) || ! isreal (radius))
+    error ("deg2nm: RADIUS must be a numeric scalar");
+  endif
+  nm = (deg2rad (deg) * radius);
+
+endfunction
+
+
+%!test
+%!assert (nm2deg (deg2nm (10)), 10, 10*eps);
+%!assert (nm2deg (deg2nm (10, 80), 80), 10, 10*eps);
+%!assert (nm2deg (deg2nm (10, "pluto"), "pluto"), 10, 10*eps);
+
+%!error <RADIUS> deg2nm (5, 5i)
diff --git a/inst/deg2sm.m b/inst/deg2sm.m
new file mode 100644
index 0000000..ea60b2a
--- /dev/null
+++ b/inst/deg2sm.m
@@ -0,0 +1,62 @@
+## Copyright (C) 2013-2020 Alexander Barth
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+##
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+##
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{sm} =} deg2sm (@var{deg})
+## @deftypefnx {Function File} {@var{sm} =} deg2sm (@var{deg}, @var{radius})
+## @deftypefnx {Function File} {@var{sm} =} deg2sm (@var{deg}, @var{sphere})
+## Converts angle n degrees to distance in statute miles by multiplying angle
+## with radius.
+##
+## Calculates the distances @var{sm} in a sphere with @var{radius} (also in
+## statute miles) for the angles @var{deg}.  If unspecified, radius defaults to
+## 3958 sm, the mean radius of Earth.
+##
+## Alternatively, @var{sphere} can be one of "sun", "mercury", "venus", "earth",
+## "moon", "mars", "jupiter", "saturn", "uranus", "neptune", or "pluto", in
+## which case radius will be set to that object's mean radius.
+##
+## @seealso{deg2km, deg2nm, km2rad, km2deg,
+## nm2deg, nm2rad, rad2km, rad2nm, rad2sm, sm2deg, sm2rad}
+## @end deftypefn
+
+## Built with insight from
+## Author: Alexander Barth <barth.alexander@gmail.com>
+## Adapted from deg2km.m by Anonymous contributor, see patch #9709
+
+function sm = deg2sm (deg, radius = "earth")
+
+  ## Check arguments
+  if (nargin < 1 || nargin > 2)
+    print_usage();
+  elseif (ischar (radius))
+    ## Get radius of sphere with its default units (km)
+    radius = km2sm (spheres_radius (radius));
+  ## Check input
+  elseif (! isnumeric (radius) || ! isreal (radius))
+    error ("deg2sm: RADIUS must be a numeric scalar");
+  endif
+  sm = (deg2rad (deg) * radius);
+
+endfunction
+
+
+%!test
+%!assert (sm2deg (deg2sm (10)), 10, 10*eps);
+%!assert (sm2deg (deg2sm (10, 80), 80), 10, 10*eps);
+%!assert (sm2deg (deg2sm (10, "pluto"), "pluto"), 10, 10*eps);
+
+%!error <RADIUS> deg2sm (5, 5i)
diff --git a/inst/degrees2dm.m b/inst/degrees2dm.m
index 36bb64a..1bfb713 100644
--- a/inst/degrees2dm.m
+++ b/inst/degrees2dm.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/degrees2dms.m b/inst/degrees2dms.m
index 444c494..3e9d9f3 100644
--- a/inst/degrees2dms.m
+++ b/inst/degrees2dms.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/degtorad.m b/inst/degtorad.m
index 25ebccf..7ac81f8 100644
--- a/inst/degtorad.m
+++ b/inst/degtorad.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/distance.m b/inst/distance.m
index 9d83dfa..d1d258e 100644
--- a/inst/distance.m
+++ b/inst/distance.m
@@ -1,5 +1,6 @@
-## Copyright (C) 2004 Andrew Collier <abcollier@users.sourceforge.net>
-## Copyright (C) 2011 Alexander Barth <abarth93@users.sourceforge.net>
+## Copyright (C) 2004-2020 Andrew Collier <abcollier@users.sourceforge.net>
+## Copyright (C) 2011-2020 Alexander Barth <abarth93@users.sourceforge.net>
+## Copyright (C) 2019-2020 Philip Nienhuis <prnienhuis@users.sf.net>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
@@ -15,16 +16,19 @@
 ## this program; if not, see <http://www.gnu.org/licenses/>.
 
 ## -*- texinfo -*-
-## @deftypefn {Function File}  {} [@var{dist},@var{az}] = distance(@var{pt1}, @var{pt2})
-## @deftypefnx {Function File} {} [@var{dist},@var{az}] = distance(@var{pt1}, @var{pt2},@var{units})
-## @deftypefnx {Function File} {} [@var{dist},@var{az}] = distance(@var{lat1},@var{lon1},@var{lat2},@var{lon2})
-## @deftypefnx {Function File} {} [@var{dist},@var{az}] = distance(@var{lat1},@var{lon1},@var{lat2},@var{lon2},@var{units})
+## @deftypefn {Function File}  {} [@var{dist}, @var{az}] = distance(@var{pt1}, @var{pt2})
+## @deftypefnx {Function File} {} [@var{dist}, @var{az}] = distance(@var{pt1}, @var{pt2},@var{units})
+## @deftypefnx {Function File} {} [@var{dist}, @var{az}] = distance(@var{lat1}, @var{lon1}, @var{lat2}, @var{lon2})
+## @deftypefnx {Function File} {} [@var{dist}, @var{az}] = distance(@var{lat1}, @var{lon1}, @var{lat2}, @var{lon2}, @var{units})
 ##
-## Calculates the great circle distance @var{dist} between @var{pt1} and @var{pt2} and optionally the azimuth @var{az}.
-## @var{pt1} and @var{pt2} are two-column matrices of the form [latitude longitude].
-## The coordinates can also be given by the parameters @var{lat1}, @var{lon1}, @var{lat2} and @var{lon2}.
-## Units can be either 'degrees' (the default) or 'radians'.
+## Calculates the great circle distance @var{dist} between @var{pt1} and
+## @var{pt2} and optionally the azimuth @var{az}.
 ##
+## @var{pt1} and @var{pt2} are two-column matrices of the form
+## [latitude longitude].
+## The coordinates can also be given by the parameters @var{lat1}, @var{lon1},
+## @var{lat2} and @var{lon2}.
+## Units can be either 'degrees' (the default) or 'radians'.
 ##
 ## @example
 ## >> distance([37,-76], [37,-9]) 
@@ -43,69 +47,68 @@
 
 ## Uses "cosine formula".
 
-function [dist,az] = distance(varargin)
-  ## default units are degrees
+function [dist, az] = distance (varargin)
 
-  units = 'degrees';
+  ## default units are degrees
+  units = "degrees";
 
-  [reg,prop] = parseparams(varargin);
+  [reg, prop] = parseparams (varargin);
 
-  if length(reg) == 2
+  if (length (reg) == 2)
     pt1 = reg{1};
     pt2 = reg{2};
 
-    a = pt1(:,1);
-    b = pt2(:,1);
-    C = pt2(:,2) - pt1(:,2);
-  elseif length(reg) == 4
+    a = pt1(:, 1);
+    b = pt2(:, 1);
+    C = pt2(:, 2) - pt1(:, 2);
+  elseif (length (reg) == 4)
     a = reg{1};
     b = reg{3};
     C = reg{4} - reg{2};
   else
-     error('Wrong number of type of arguments');
-  end
+     error ("Wrong number or type of arguments");
+  endif
 
-  if length(prop) == 1
+  if (length (prop) == 1)
     units = prop{1};
 
-    if (~strcmp(units,'degrees') && ~strcmp(units,'radians'))
-      error('Only degrees and radians are allowed as units');
-    end
-  elseif length(prop) > 1
-    error('Wrong number of type of arguments');
-  end
+    if (! strcmp (units, "degrees") && ! strcmp (units, "radians"))
+      error ("Only degrees and radians are allowed as units");
+    endif
+  elseif (length(prop) > 1)
+    error ("Wrong number of type of arguments");
+  endif
 
-  if (strcmp(units,'degrees'))
-    a = deg2rad(a);
-    b = deg2rad(b);
-    C = deg2rad(C);
-  end
+  if (strcmp (units, "degrees"))
+    a = deg2rad (a);
+    b = deg2rad (b);
+    C = deg2rad (C);
+  endif
 
-  dist = acos(sin(b) .* sin(a) + cos(b) .* cos(a) .* cos(C));
+  dist = acos (sin (b) .* sin (a) + cos (b) .* cos (a) .* cos (C));
 
-  if (strcmp(units,'degrees'))
-     dist = rad2deg(dist);
-  end
+  if (strcmp (units, "degrees"))
+     dist = rad2deg (dist);
+  endif
 
-  if nargout == 2
-    az = atan2(sin(C) , cos(a) .* tan(b) - sin(a) .* cos(C) );
+  if (nargout == 2)
+    az = atan2 (sin(C), cos (a) .* tan (b) - sin (a) .* cos (C));
 
     ## bring the angle in the interval [0 2*pi[
-
-    az = mod(az,2*pi);
+    az = mod(az, 2 * pi);
 
     ## convert to degrees if desired
-
-    if (strcmp(units,'degrees'))
-       az = rad2deg(az);
-    end
-  end
+    if (strcmp (units, "degrees"))
+       az = rad2deg (az);
+    endif
+  endif
 
 endfunction
 
-%!assert(distance([37,-76], [37,-9]), 52.30942093, 1e-7)
+
+%!assert (distance ([37, -76], [37, -9]), 52.30942093, 1e-7)
 
 %!test
-%! [d,az] = distance(0,0, 0,pi,'radians');
-%! assert(d,pi,1e-7)
-%! assert(az,pi/2,1e-7)
+%! [d, az] = distance (0, 0, 0, pi, "radians");
+%! assert (d, pi, 1e-7)
+%! assert (az, pi / 2, 1e-7)
diff --git a/inst/dm2degrees.m b/inst/dm2degrees.m
index 861f0cc..7d560d6 100644
--- a/inst/dm2degrees.m
+++ b/inst/dm2degrees.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/dms2degrees.m b/inst/dms2degrees.m
index 51b5993..69bc5cd 100644
--- a/inst/dms2degrees.m
+++ b/inst/dms2degrees.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/dxfdraw.m b/inst/dxfdraw.m
new file mode 100644
index 0000000..d70da84
--- /dev/null
+++ b/inst/dxfdraw.m
@@ -0,0 +1,178 @@
+## Copyright (C) 2016-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} [@var{h}] = dxfdraw (@var{dxf})
+## @deftypefnx {} [@var{h}] = dxfdraw (@var{dxf}, @var{clr})
+## @deftypefnx {} [@var{h}] = dxfdraw (@dots{}, @var{name}, @var{value}, @dots{})
+## Draw a map of a DXF file based on a DXF cell array or DXF drawing struct.
+##
+## Input argument @var{dxf} is the name of a DXF cell array (see
+## dxfread.m), or the name of a DXF file, or a DXF drawing struct made
+## by dxfparse.
+##
+## @var{clr} is the color used to draw the DXF contents.  All lines and
+## arcs are drawn in the same color; similar for all filled surfaces.  
+## For points, lines and polylines this can be a 3x1 RGB vector or a color
+## code. For polygons it can be a 2x1 vector of color codes or a 2x3 double
+## array of RGB entries.  The default is [0.7 0.7 0.7; 0.8 0.9 0.99].
+##
+## In addition several graphics properties can be specified, e.g., linestyle
+## and linewidth. No checks are performed whether these are valid for the
+## entities present in the DXF cell array or file.
+##
+## Currently the following entities are supported: POINT, LINE, POLYLINE,
+## LWPOLYLINE, CIRCLE, ARC and 3DFACE.  For drawing CIRCLE and ARC entities
+## functions from the geometry packge are required.
+##
+## Optional output argument @var{h} is the graphics handle of the resulting
+## map.
+##
+## @seealso{dxfread, dxfparse}
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2016-01-25
+
+function [h] = dxfdraw (dxf, clr=[0.7 0.7 0.7; 0.8 0.9 0.99], varargin)
+
+  if (isstruct (dxf))
+    ## Cursory validation
+    fldnm = fieldnames (dxf);
+    if (! all (ismember({"i3d", "ic", "ia", "j3", "jr", "il", "ip"}, fldnm)))
+      error ("dxfdraw: invalid struct input for arg #1");
+    endif
+
+  else
+    if (isempty (dxf))
+      return
+
+    elseif (iscell (dxf))
+      ## Cursory Q-checks: minumum 3 columns, col 1 & 3 numeric, col #2 character
+      if (size (dxf, 2) < 3 || ! all (all (cellfun (@isnumeric, dxf(:, [1, 3])))) ...
+          || ! all (cellfun (@ischar, dxf(:, 2))))
+        error ("dxfdraw: input arg #1 does not look like a valid dxf cell array");
+      endif
+
+    elseif (ischar (dxf))
+      ## Maybe a DXF file?
+      [~, ~, ext] = fileparts (dxf);
+      if (isempty (ext) || ! strcmpi (ext, ".dxf"))
+        ## Just add a .dxf suffix
+        dxf = [dxf ".dxf"];
+      endif
+      fid = fopen (dxf);
+      if (fid < 0)
+        error ("File '%s' not found", dxf);
+      else
+        fclose (fid);
+      endif
+      ## Read DXF file into DXF cell array
+      dxf = dxfread (dxf);
+
+    else
+      error ("dxfdraw: DXF cell array, DXF file name, or DXF drawing struct \
+expected for arg #1 ");
+    endif
+  
+    ## parse DXF cell array into a DXF drawing struct
+    dxf = dxfparse (dxf, 0);
+  endif
+
+  ## We should have a valid struct now. Extract data
+  i3d = dxf.i3d;
+  is = dxf.is;
+  ir = dxf.ir;
+  ic = dxf.ic;
+  ia = dxf.ia;
+  j3 = dxf.j3;
+  jr = dxf.jr;
+  il = dxf.il;
+  ip = dxf.ip;
+  jf = dxf.jf;
+  jw = dxf.jw;
+  jl = dxf.jl;
+  XYZ = dxf.XYZ;
+  XYZp = dxf.XYZp;
+  XY = dxf.XY;
+  CIRCLES = dxf.CIRCLES;
+  ARCS = dxf.ARCS;
+  VRT3 = dxf.VRT3;
+  FAC3 = dxf.FAC3;
+  LWP = dxf.LWP;
+  LWV = dxf.LWV;
+  VRTS = dxf.VRTS;
+  FACP = dxf.FACP;
+  ## dxf not needed from here, clear it as it may hold lots of RAM needed for plot
+  clear dxf;
+
+  h = figure ();
+  hold on;
+  axis equal;
+
+  if (i3d)
+    if (is > 0)
+      plot3 (XYZp(:, 1), XYZp(:, 2), XYZp(:, 3), "color", clr(1, :), varargin{:});
+    endif
+    if (ir > 0)
+      plot3 (XYZ(:, 1), XYZ(:, 2), XYZ(:, 3), "color", clr(1, :), varargin{:});
+    endif
+    if (ic > 0)
+      drawCircle3d (CIRCLES, "color", clr(1, :), varargin{:});
+    endif
+    if (ia > 0)
+      drawCircleArc3d (ARCS, "color", clr(1, :), varargin{:});
+    endif
+    if (j3 > 0)
+      patch ("vertices", VRT3, "faces", FAC3, "edgecolor", clr(1, :), ...
+             "facecolor", clr(2, :), varargin{:}); 
+    endif
+
+  else
+    if (is > 0)
+      plot (XYZp(:, 1), XYZp(:, 2), "color", clr(1, :), varargin{:});
+    endif
+    if (ir > 0)
+      plot (XYZ(:, 1), XYZ(:, 2), "color", clr(1, :), varargin{:});
+    endif
+    if (ic > 0)
+      drawCircle (CIRCLES, "color", clr(1, :), varargin{:});
+    endif
+    if (ia > 0)
+      drawCircleArc (ARCS, "color", clr(1, :), varargin{:});
+    endif
+    if (jr > 0)
+      plot (XY(:, 1), XY(:, 2), "color", clr(1, :), varargin{:});
+    endif
+    if (il > 0)
+      LWV(jw+1:end, :) = [];
+      LWV(LWV == 0) = NaN;
+      patch ("vertices", LWP, "faces", LWV, "edgecolor", clr(1, :), ...
+            "facecolor", clr(2, :), varargin{:}); 
+    endif
+
+  endif
+
+  if (ip > 0)
+    FACP(jf+1:end, :) = [];
+    FACP(FACP == 0) = NaN;
+    if (! i3d)
+      VRTS(:, 3) = [];
+    endif
+    patch ("vertices", VRTS, "faces", FACP, "edgecolor", clr(1, :), ...
+           "facecolor", clr(2, :), varargin{:});
+  endif
+
+endfunction
diff --git a/inst/dxfparse.m b/inst/dxfparse.m
new file mode 100644
index 0000000..15e3f39
--- /dev/null
+++ b/inst/dxfparse.m
@@ -0,0 +1,477 @@
+## Copyright (C) 2017-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} {@var{dxfo} =} dxfparse (@var{dxfi})
+## @deftypefnx {} {@var{dxfo} =} dxfparse (@var{dxfi}, @var{outstyle})
+## Parse a DXF struct (read by dxfread) into a DXF drawing struct or
+## into a mapstruct.
+##
+## Input arg @var{dxfi} can be a DXF cell array produced by dxfread, or a
+## DXF file name (dxfparse will invoke dfread to read it).
+##
+## Optional numeric input argument @var{outstyle} can be used to select
+## a desired output format:
+##
+## @itemize
+## @item 0 (default)
+## Return an output struct optimized for fast drawing with dxfdraw.m
+##
+## @item 1
+## Return an output struct containing 2D (Matlab-compatible) mapstructs
+## like those returned by shaperead.m.  The output struct contains a "dxfpl"
+## Polyline mapstruct for LINEs and open POLYLINEs and LWPOLYLINE entities;
+## a "dxfpt" Point mapstruct for POINT entities; and a "dxfpg" Polygon
+## mapstucts for closed POLYLINE and LWPOLYLINE entities.
+##
+## @item 2
+## If the DXF file is 3D, return a 3D mapstruct as returned by shaperead.m
+## with Z coordinates.
+## @end itemize
+##
+## @seealso{dxfread, dxfdraw}
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2017-01-07
+
+function [dxfo] = dxfparse (dxfi, outstyle=0)
+
+  if (isempty (dxfi))
+    return
+
+  elseif (iscell (dxfi))
+    ## Cursory Q-checks: minumum 3 columns, col 1 & 3 numeric, col #2 character
+    if (size (dxfi, 2) < 3 || ! all (all (cellfun (@isnumeric, dxfi(:, [1, 3])))) ...
+        || ! all (cellfun (@ischar, dxfi(:, 2))))
+      error ("dxfdraw: input arg #1 does not look like a valid dxf cell array");
+    endif
+
+  elseif (ischar (dxfi))
+    ## Maybe a DXF file?
+    [~, ~, ext] = fileparts (dxfi);
+    if (isempty (ext) || ! strcmpi (ext, ".dxf"))
+      ## Just add a .dxf suffix
+      dxfi = [dxfi ".dxf"];
+    endif
+    fid = fopen (dxfi);
+    if (fid < 0)
+      error ("File '%s' not found", dxfi);
+    else
+      fclose (fid);
+    endif
+    ## Read DXF file
+    dxfi = dxfread (dxfi);
+
+  else
+    error ("dxfdraw: DXF cell array or DXF file name expected for arg #1 ");
+  endif
+
+  ## Interpret DXF struct
+  ## 1. Cast numeric parts of dxf into double to speed up processing
+  dxfn = cell2mat (dxfi(:, [1, 3]));
+
+  ## 2. Find extent of different ENTITIES in file
+  idx = find (dxfn(:, 1) == 0);
+  idx(idx < strmatch ("ENTITIES", dxfi(:, 2))) = [];
+  idx(find (ismember (idx, strmatch ("VERTEX", dxfi(:, 2))))) = [];
+  idx(find (ismember (idx, strmatch ("SEQEND", dxfi(:, 2))))) = [];
+
+  ## 3. Is DXF 3D or not
+  iz = find (cell2mat (dxfi(:, 1)) == 30);
+  i3d = ! isempty (iz) && any (abs (cell2mat (dxfi(iz, 3))) > eps);
+
+  ## 4. Preallocate XYZp array for POINTS
+  ns = numel (strmatch ("POINT", dxfi(:, 2)));
+  is = 0;                                         ## Pointer array row counter
+  if (outstyle == 0)
+    XYZp = NaN (ns*2-1, 3);
+    plyrs = cell (ns, 1);
+  else
+    ## Preallocate 2D mapstruct. If Z is needed it'll be added automatically
+    ## the first time it is referenced in one action
+    dxfpt = repmat (struct ("Geometry", "Point", ...
+                            "X",        NaN, ...
+                            "Y",        NaN), ns, 1);
+  endif
+
+  ## 5. Preallocate XYZ array to hold LINE & POLYLINE coordinates.
+  ## 2 rows + NaN row for all LINE entities
+  nr = numel (strmatch ("LINE", dxfi(:, 2))) * 3;
+  ## 1 NaN row for each POLYLINE
+  np = numel (strmatch ("POLYLINE", dxfi(:, 2)));
+  nr += np;
+  jl = jp = 0;
+  if (outstyle == 0)
+    ## Allocate layer info
+    llyrs = cell (np+nr/3, 1);
+    ## 1 row for each VERTEX
+    nr += numel (strmatch ("VERTEX", dxfi(:, 2)));
+    ## Avoid trailing NaN row
+    XYZ = NaN (nr-1, 3);
+    ir = 0;                                       ## (poly)lines / llyrs row index
+    ## Vertices for polygons
+    VRTS = NaN (nr-1, 3);
+    ## Allocate provisionally 100 vertices per facet
+    FACP = NaN (np, 100);
+    ip = jf = 0;                                  ## polygon vertices/faces row indices
+  else
+    ## We can't foretell which POLYLINES are closed or open ==> assign struct
+    ## arrays large enough for polygons and polylines alike
+    dxfpl = repmat (struct ("Geometry",    "Polyline", ...
+                            "BoundingBox", NaN (2, 2), ...
+                            "X",           NaN, ...
+                            "Y",           NaN), nr, 1);
+    dxfpg = repmat (struct ("Geometry",    "Polygon", ...
+                            "BoundingBox", NaN (2, 2), ...
+                            "X",           NaN, ...
+                            "Y",           NaN), nr, 1);
+  endif
+
+  ## 6. LWPOLYLINE - no real preallocation yet, will be extended incrementally
+  nw = numel (strmatch ("LWPOLYLINE", dxfi(:, 2)));
+  wlyrs = cell (nw, 1);
+  if (outstyle == 0)
+    LWP = NaN (5000, 2);
+    LWV = NaN (250, 100);
+    il = jw = jr = iw = 0;                        ## polyline vertices/faces/lyrs row indices
+    XY = NaN (5000, 2);
+  else
+    ## Extend Polyline/-gon arrays. If we have LWPOLYLINE the DXF file is 2D
+    dxfpl = repmat (struct ("Geometry",    "Polyline", ...
+                            "BoundingBox", NaN (2, 2), ...
+                            "X",           NaN, ...
+                            "Y",           NaN), nr+nw, 1);
+    dxfpg = repmat (struct ("Geometry",    "Polygon", ...
+                            "BoundingBox", NaN (2, 2), ...
+                            "X",           NaN, ...
+                            "Y",           NaN), nr+nw, 1);
+  endif
+
+  ## 7. Preallocate array for CIRCLEs
+  nc = numel (strmatch ("CIRCLE", dxfi(:, 2)));
+  if (i3d)
+    CIRCLES = zeros (nc, 4);
+  else
+    CIRCLES = zeros (nc, 3);
+  endif
+  ic = 0;                                         ## Circle row counter
+  clyrs = cell (nc, 1);
+
+  ## 8. Preallocate array for ARCs
+  na = numel (strmatch ("ARC", dxfi(:, 2), "exact"));
+  if (i3d)
+    ARCS = zeros (na, 6);
+  else
+    ARCS = zeros (na, 5);
+  endif
+  ia = 0;                                         ## Arc row counter
+  alyrs = cell (na, 1);
+
+  ## 9. Preallocate 3DFACE array
+  n3 = numel (strmatch ("3DFACE", dxfi(:, 2)));
+  VRT3 = NaN (4*n3, 3);
+  FAC3 = NaN (n3, 5);
+  iv = j3 = id = 0;                               ## 3Dface / dlyrs row counter
+  dlyrs = cell (n3, 1);
+
+  ## 10. Start interpreting. For each ENTITY:
+  for ii=1:numel (idx) - 1
+    switch dxfi{idx(ii), 2}
+
+      case "POINT"
+        x1 = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 10) + idx(ii)-1, 2);
+        y1 = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 20) + idx(ii)-1, 2);
+        z1 = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 30) + idx(ii)-1, 2);
+        lb = dxfi(find (dxfn(idx(ii):idx(ii+1), 1) == 8) + idx(ii)-1, 2){1};
+        if (outsyle == 0)
+          ## X, Y [,Z] coordinates
+          XYZp(++is, 1) = x1;
+          XYZ(is, 2)    = y1;
+          if (i3d)
+            XYZp(is, 3) = z1;
+          endif
+          plyrs{is} = lb;
+          ## Leave NaN row before next point
+          ++is;
+        else
+          dxfpt(++is).Geometry = "Point";
+          dxfpt(is).X = x1;
+          dxfpt(is).Y = y1;
+          if (outstyle == 2 && i3d)
+            dxfpt(is).Z = z1;
+          endif
+          dxfpt(is).LAYER = lb;
+          dxfpt(is)._SOURCE_ = "DXF_POINT";
+        endif
+
+      case "LINE"
+        ## X, Y [,Z] coordinates of end points
+        x1 = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 10) + idx(ii)-1, 2);
+        y1 = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 20) + idx(ii)-1, 2);
+        x2 = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 11) + idx(ii)-1, 2);
+        y2 = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 21) + idx(ii)-1, 2);
+        lb = dxfi(find (dxfn(idx(ii):idx(ii+1), 1) == 8) + idx(ii)-1, 2){1};
+        if (i3d)
+          z1 = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 30) + idx(ii)-1, 2);
+          z2 = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 31) + idx(ii)-1, 2);
+        endif
+        if (outstyle == 0)
+          XYZ(++ir, 1) = x1;
+          XYZ(ir, 2)   = y1;
+          XYZ(++ir, 1) = x2;
+          XYZ(ir, 2)   = y2;
+          if (i3d)
+            XYZ(ir-1, 3) = z1;
+            XYZ(ir, 3)   = z2;
+          endif
+          llyrs{++jl} = lb;
+          ++ir;
+        else
+          dxfpl(++jl).Geometry = "Polyline";
+          dxfpl(jl).X = [x1 x2];
+          dxfpl(jl).Y = [y1 y2];
+          dxfpl(jl).BoundingBox = [min(x1, x2) min(y1, y2); max(x1, x2) max(y1, y2)];
+          if (outstyle == 2 && i3d)
+            dxfpl(jl).Z = [z1 z2];
+          endif
+          dxfpl(jl).LAYER = lb;
+          dxfpl(jl)._SOURCE_ = "DXF_LINE";
+        endif
+
+      case "POLYLINE"
+        ## Find nr. of vertices
+        jv = strmatch ("VERTEX", dxfi(idx(ii):idx(ii+1), 2)) + idx(ii) - 1;
+        nv = numel (jv);
+        ## Get polyline flag and check if it's a closed one (i.e., a polygon)
+        pflags = uint8 (dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 70) + idx(ii) - 1, 2));
+        ## Polygon / closed polyline. Get vertices
+        xx = dxfn(find (dxfn(jv(1):idx(ii+1), 1) == 10) + jv(1) - 1, 2);
+        yy = dxfn(find (dxfn(jv(1):idx(ii+1), 1) == 20) + jv(1) - 1, 2);
+        lb = dxfi(find (dxfn(idx(ii):idx(ii+1), 1) == 8) + idx(ii)-1, 2){1};
+        if (i3d)
+          zz = dxfn(find (dxfn(jv(1):idx(ii+1), 1) == 30) + jv(1) - 1, 2);
+        endif
+        if (outstyle == 0)
+          if (bitget (pflags, 1))
+            ## Polygon / closed polyline. Get vertices
+            VRTS(++ip:ip+nv-1, 1) = xx;
+            VRTS(ip:ip+nv-1, 2)   = yy;
+            if (i3d)
+              VRTS(ip:ip+nv-1, 3) = zz;
+            endif
+            ip += nv - 1;
+            ++jf;
+            ## Update faces
+            FACP(jf, 1:nv+1) = [ (ip-nv + 1 : ip) (ip - nv + 1) ];
+          else
+            ## Open polyline
+            XYZ(++ir:ir+nv-1, 1) = xx;
+            XYZ(ir:ir+nv-1, 2)   = yy;
+            if (i3d)
+              XYZ(ir:ir+nv-1, 3) = zz;
+            endif
+            ir += nv;
+          endif
+          llyrs(++jl) = lb;
+        else
+          if (bitget (pflags, 1))
+            ## Polygon / closed polyline
+            dxfpg(++jp).Geometry = "Polygon";
+            dxfpg(jp).X = xx';
+            dxfpg(jp).Y = yy';
+            dxfpg(jp).BoundingBox = [min(xx) min(yy); max(xx) max(yy)];
+            if (outstyle == 2 && i3d)
+              dxfpg(jp).Z = zz';
+            endif
+            dxfpg(jp).LAYER = lb;
+            dxfpg(jp)._SOURCE_ = "DXF_POLYLN";
+          else
+            dxfpl(++jl).Geometry = "Line";
+            dxfpl(jl).X = xx';
+            dxfpl(jl).Y = yy';
+            dxfpl(jl).BoundingBox = [min(xx) min(yy); max(xx) max(yy)];
+            if (outstyle == 2 && i3d)
+              dxfpl(jl).Z = zz';
+            endif
+            dxfpl(jl).LAYER = lb;
+            dxfpl(jl)._SOURCE_ = "DXF_POLYLN";
+          endif
+        endif
+
+      case "LWPOLYLINE"
+        if (i3d)
+          error ("Inconsistent DXF input - LWPOLYLINE = 2D but there are 3D entities");
+        endif
+        ## Nr. of vertices
+        nw = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 90) + idx(ii)-1, 2);
+        xx = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 10) + idx(ii)-1, 2);
+        yy = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 20) + idx(ii)-1, 2);
+        lb = dxfi(find (dxfn(idx(ii):idx(ii+1), 1) ==  8) + idx(ii)-1, 2){1};
+        ## Get polyline flag and check if it's a closed one (i.e., a polygon)
+        pflags = uint8 (dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 70) + idx(ii) - 1, 2));
+        if (outstyle == 0)
+          if (bitget (pflags, 1))
+            ## Closed polyline
+            if (il + nw > size (LWP, 1))
+              ## Extend LWP array (vertices)
+              LWP = [LWP ; NaN(5000, 2)];
+            endif
+            if (jw + 1 > size (LWV, 1))
+              ## Extend LWV array (faces)
+              LWV = [LWV ; NaN(250, size(LWV, 2))];
+            endif
+            LWP(il+1:il+nw, 1) = xx;
+            LWP(il+1:il+nw, 2) = yy;
+            ++jw;
+            LWV(jw, 1:nw+1) = [ (il+1 : il+nw) (il + 1) ];
+            il += nw - 1;
+          else
+            ## Open polyline
+            if (jr + nw + 1 > size (XY, 1))
+              ## Extend XY array
+              XY = [XY ; XY(5000, 2)];
+            endif
+            XY(jr+1:jr+nw, 1) = xx;
+            XY(jr+1:jr+nw, 2) = yy;
+            jr += nw;
+          endif
+          wlyrs(++iw) = lb;
+        else
+          if (bitget (pflags, 1))
+            ## Polygon / closed polyline
+            dxfpg(++jp).Geometry = "Polygon";
+            dxfpg(jp).X = xx';
+            dxfpg(jp).Y = yy';
+            dxfpg(jp).BoundingBox = [min(xx) min(yy); max(xx) max(yy)];
+            dxfpg(jp).LAYER = lb;
+            dxfpg(jp)._SOURCE_ = "DXF_LWPOLY";
+          else
+            dxfpl(++jl).Geometry = "Line";
+            dxfpl(jl).X = xx';
+            dxfpl(jl).Y = yy';
+            dxfpl(jl).BoundingBox = [min(xx) min(yy); max(xx) max(yy)];
+            dxfpl(jl).LAYER = lb;
+            dxfpl(jl)._SOURCE_ = "DXF_LWPOLY";
+          endif
+        endif
+
+      case "CIRCLE"
+        if (outstyle == 0)
+          ## Get center point
+          CIRCLES(++ic, 1) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 10) + idx(ii)-1, 2);
+          CIRCLES(ic, 2)   = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 20) + idx(ii)-1, 2);
+          if (i3d)
+            CIRCLES(ic, 3) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 30) + idx(ii)-1, 2);
+            CIRCLES(ic, 4) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 40) + idx(ii)-1, 2);
+          else
+            CIRCLES(ic, 3) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 40) + idx(ii)-1, 2);
+          endif
+          clyrs(ic) = dxfi(find (dxfn(idx(ii):idx(ii+1), 1) == 8) + idx(ii)-1, 2){1};
+        endif
+
+      case "ARC"
+        if (outstyle == 0)
+          ## Get center point
+          ARCS(++ia, 1) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 10) + idx(ii)-1, 2);
+          ARCS(ia, 2)   = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 20) + idx(ii)-1, 2);
+          if (i3d)
+            ARCS(ia, 3) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 30) + idx(ii)-1, 2);
+            ARCS(ia, 4) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 40) + idx(ii)-1, 2);
+            ARCS(ia, 5) = wrapTo180 (dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 50) + idx(ii)-1, 2));
+            ARCS(ia, 6) = wrapTo180 (dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 51) + idx(ii)-1, 2)) - ARCS(ia, 5);
+            if (ARCS(ia, 6) < 0)
+              ARCS(ia, 6) = wrapTo360 (ARCS(ia, 6));
+            endif
+          else
+            ARCS(ia, 3) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 40) + idx(ii)-1, 2);
+            ARCS(ia, 4) = wrapTo180 (dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 50) + idx(ii)-1, 2));
+            ARCS(ia, 5) = wrapTo180 (dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 51) + idx(ii)-1, 2)) - ARCS(ia, 4);
+            if (ARCS(ia, 5) < 0)
+              ARCS(ia, 5) = wrapTo360 (ARCS(ia, 5));
+            endif
+          endif
+          alyrs{ia} = dxfi(find (dxfn(idx(ii):idx(ii+1), 1) == 8) + idx(ii)-1, 2){1};
+        endif
+
+      case "3DFACE"
+        if (outstyle == 0)
+          VRT3(++iv, 1) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 10) + idx(ii)-1, 2);
+          VRT3(iv, 2)   = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 20) + idx(ii)-1, 2);
+          VRT3(iv, 3)   = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 30) + idx(ii)-1, 2);
+          VRT3(++iv, 1) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 11) + idx(ii)-1, 2);
+          VRT3(iv, 2)   = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 21) + idx(ii)-1, 2);
+          VRT3(iv, 3)   = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 31) + idx(ii)-1, 2);
+          VRT3(++iv, 1) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 12) + idx(ii)-1, 2);
+          VRT3(iv, 2)   = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 22) + idx(ii)-1, 2);
+          VRT3(iv, 3)   = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 32) + idx(ii)-1, 2);
+          VRT3(++iv, 1) = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 13) + idx(ii)-1, 2);
+          VRT3(iv, 2)   = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 23) + idx(ii)-1, 2);
+          VRT3(iv, 3)   = dxfn(find (dxfn(idx(ii):idx(ii+1), 1) == 33) + idx(ii)-1, 2);
+          ++j3;
+          FAC3(j3, :) = [ ((j3-1)*4+1 : (j3-1)*4+4) (j3-1)*4+1 ];
+          ++id;
+          dlyrs{id, 1} = dxfi(find (dxfn(idx(ii):idx(ii+1), 1) == 8) + idx(ii)-1, 2){1};
+        endif
+
+      otherwise
+        ## Ignored entities
+
+    endswitch
+  endfor
+
+  ## Put all info in a struct to speed up redrawing
+  if (outstyle == 0)
+    dxfo.i3d = i3d;
+    dxfo.is = is;
+    dxfo.ir = ir;
+    dxfo.ic = ic;
+    dxfo.ia = ia;
+    dxfo.j3 = j3;
+    dxfo.jr = jr;
+    dxfo.il = il;
+    dxfo.ip = ip;
+    dxfo.jf = jf;
+    dxfo.jw = jw;
+    dxfo.jl = jl;
+    dxfo.XYZ = XYZ;
+    dxfo.XYZp = XYZp;
+    if (il > 0)
+      dxfo.LWP = LWP(1:il+1, :);
+      dxfo.LWV = LWV(1:jw, :);
+      LWV(LWV == 0) = NaN;
+    else
+      dxfo.LWP = dxfo.LWV = [];
+    endif
+    dxfo.XY = XY(1:jr, :);
+    dxfo.CIRCLES = CIRCLES;
+    dxfo.ARCS = ARCS;
+    dxfo.VRT3 = VRT3;
+    dxfo.FAC3 = FAC3;
+    dxfo.VRTS = VRTS;
+    dxfo.FACP = FACP;
+  else
+    if (is > 0)
+      dxfo.dxfpt = dxfpt;
+    endif
+    if (jl > 0)
+      dxfo.dxfpl = dxfpl(1:jl);
+    endif
+    if (jp > 0)
+      dxfo.dxfpg = dxfpg(1:jp);
+    endif
+  endif
+
+endfunction
diff --git a/inst/dxfread.m b/inst/dxfread.m
new file mode 100644
index 0000000..6dd0eb3
--- /dev/null
+++ b/inst/dxfread.m
@@ -0,0 +1,72 @@
+## Copyright (C) 2016-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} {@var{dxf} =} dxfread (@var{fname})
+## Read a DXF file (text file) into a Nx3 cell array.
+##
+## @var{fname} is the file name or full path name of a text format (not
+## binary) DXF file, with or without "dxf" extension.
+##
+## Output variable @var{dxf} is a cell array with DXF codes in column 1,
+## the corresponding DXF text info (or empty string) in column 2, and
+## corresponding numeric values (or NaN) in column 3.  Use dxfparse for
+## converting the output into a DXF drawing struct or separate mapstructs
+## for each ENTITY type in the DXF file.
+##
+## @seealso{dxfparse, dxfdraw}
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2016-01-25
+
+function [dxf] = dxfread (fname)
+
+  if (! ischar (fname))
+    print_usage ();
+  endif
+
+  [pth, fn, ext] = fileparts (fname);
+  if (isempty (ext))
+    ext = ".dxf";
+    fname = [fname ext];
+  elseif (! strcmpi (ext, ".dxf"))
+    error ("dxfread: file is no .DXF file");
+  endif
+
+  fid = fopen (fname);
+  if (fid < 0)
+    error ("file %s not found", fname);
+  else
+    txt = fread (fid, Inf, "char=>char")'; 
+    fclose (fid);
+  endif
+
+  ## Assess EOL character
+  eol = regexp (txt(1: min (2000, length (txt))), "\r\n", "match", "once");
+  if (isempty (eol))
+    eol = "\n";
+  endif
+
+  ## DXF files comprise pairs of lines: 1st line = numeric code, 2nd = contents
+  dxf = reshape (cell2mat ( ...
+        regexp (txt, sprintf ('(\\d+)%s(.+?)%s', eol, eol), "tokens")), 2, [])';
+  ## Convert col 1 into numeric
+  dxf(:, 1) = num2cell (str2double (dxf(:, 1)));
+  ## Convert numeric entries in col2 into numeric col3
+  dxf(:, 3) = num2cell (str2double (dxf(:, 2)));
+  dxf(! cellfun (@isnan, dxf(:, 3)), 2) = {""};
+
+endfunction
diff --git a/inst/earthRadius.m b/inst/earthRadius.m
new file mode 100644
index 0000000..74aa0f0
--- /dev/null
+++ b/inst/earthRadius.m
@@ -0,0 +1,50 @@
+## Copyright (C) 2017-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} earthRadius (@var{unit})
+## Converts the Earth's radius into other units.
+##
+## Input argument @var{units} can be one of the units of validateLengthUnit.
+## The default is meters.
+##
+## @example
+## earthRadius ('km')
+## => ans = 6371
+## @end example
+##
+## @seealso {validateLengthUnit,unitsratio}
+## @end deftypefn
+
+function R = earthRadius (unit)
+
+  radius = spheres_radius ("earth") * 1000;    ## This is the default in meters
+  if (nargin == 0)
+    R = radius; 
+  elseif (nargin > 1)
+    print_usage ();
+  elseif ( ! ischar( unit ) )
+    error ("earthRadius.m: string value expected");
+  else
+    ratio = unitsratio (unit , "Meters");
+    R = radius * ratio;
+  endif
+
+endfunction
+
+%!test
+%! radius = earthRadius / 1000;;
+%! assert (earthRadius ("km"), radius);
diff --git a/inst/ecc2flat.m b/inst/ecc2flat.m
new file mode 100644
index 0000000..6d05f7b
--- /dev/null
+++ b/inst/ecc2flat.m
@@ -0,0 +1,66 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+##
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+##
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{flat} =} flat2ecc (@var{ecc}) 
+## Return flattening given an eccentricity 
+##
+## Exmples:
+##
+## Scalar input:
+## @example
+##  e_earth = .081819221456;
+##  f_earth = ecc2flat (e_earth) 
+##  => f_earth = 0.0033528 
+## @end example
+##
+## Vector input:
+## @example
+##  ec = 0 : .01 : .05;
+##  f = ecc2flat (ec)
+##  => f =
+##        0.0000000   0.0000500   0.0002000   0.0004501   0.0008003   0.0012508
+## @end example
+## 
+## @seealso{flat2ecc}
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9492
+
+function ff = ecc2flat (ec)  
+
+  if nargin < 1
+    print_usage ();
+  endif
+
+  if (! isnumeric (ec))
+    error ("ecc2flat.m: numeric input expected");
+  elseif (any (ec < 0) || any (ec >= 1))
+    error ("ecc2flat.m: eccentricity must lie in the real interval [0..1)");
+  else
+    ff = 1 - sqrt (1 - ec.^2);
+  endif
+
+endfunction 
+
+%!test
+%! ec = 0.081819221456;
+%! ev = 0 : 0.01 : 0.05;
+%! assert (ecc2flat (ec), 0.00335281317793612, 10^-12);
+%! assert (ecc2flat (ev), [0, 5e-5, 2e-4, 4.501e-4, 8.0032e-4, 0.00125078], 10^-6);
+
+%!error <numeric input expected> ecc2flat ("a")
+%!error <eccentricity> ecc2flat(1)
diff --git a/inst/ecc2n.m b/inst/ecc2n.m
new file mode 100644
index 0000000..cabea91
--- /dev/null
+++ b/inst/ecc2n.m
@@ -0,0 +1,79 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{n} =} ecc2n (@var{ecc})
+## This returns the third flattening given an eccentricity.
+##
+## Examples:
+##
+## Scalar input:
+## @example
+##  e_earth = 0.081819221456;
+##  n_earth = ecc2n (e_earth)
+##  => n_earth = 0.0016792
+## @end example 
+##
+## Vector input:
+## @example
+##  e_vec = [ 0.081819221456  0.3543164 ]
+##  n = ecc2n (e_vec)
+##  => n =
+##	 0.0016792    0.033525
+## @end example
+##
+## @seealso{n2ecc}
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9566
+## For background see https://en.wikipedia.org/wiki/Flattening
+
+function n = ecc2n ( ecc )
+  
+  if (nargin < 1)
+    print_usage ();
+  end
+  
+  if (! isnumeric (ecc) || ! isreal (ecc))
+    error ("ecc2n.m: numeric input expected");
+  elseif (any (ecc < 0) || any (ecc > 1))
+    error ("ecc2n.m: eccentricity should lie in real interval [0..1]")
+  else
+    B = (4 ./ ecc.^2 - 2); ## Taken from e^2 = 4n / (1+n)^2
+    ## Use to get in the form n^2 - Bn + 1 = 0
+    ## From testing the other definition of third flattening (a-b)/(a+b)
+    ## Use the - version for the quadratic equation
+    n = (B - sqrt (B .^2 - 4)) ./ 2;
+  end
+
+endfunction
+
+%!test
+%!
+%! ecc_earth = .081819221456;
+%! ecc_jupiter =  0.3543164;
+%! e_vec = [ ecc_earth ecc_jupiter ];
+%! assert ( ecc2n ( ecc_earth ) , 0.001679222 , 10e-10 ); 
+%! assert ( ecc2n ( e_vec ), [0.0016792    0.03352464],10e-8);
+
+%!error <numeric input expected> ecc2n ("ecc")
+%!error <numeric input expected> ecc2n (0.5 + 3i)
+%!error <n should lie> n2ecc (-1)
+%!error <n should lie> n2ecc (2)
+%!error <n should lie> n2ecc (-Inf)
+%!error <n should lie> n2ecc (Inf)
+
diff --git a/inst/ecef2geodetic.m b/inst/ecef2geodetic.m
new file mode 100644
index 0000000..ec17879
--- /dev/null
+++ b/inst/ecef2geodetic.m
@@ -0,0 +1,174 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+## 
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+## 
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{lat}, @var{lon}, @var{alt} =} ecef2geodetic (@var{spheroid}, @var{X}, @var{Y}, @var{Z}) 
+## @deftypefnx  {Function File} {@var{lat}, @var{lon}, @var{alt} =} ecef2geodetic (@var{X}, @var{Y}, @var{Z}) 
+## @deftypefnx  {Function File} {@var{lat}, @var{lon}, @var{alt} =} ecef2geodetic (@dots{}, @var{angleUnit}) 
+## Converts from ecef coordinate frame to geodetic coordinate frame.
+##
+## Optional argument @var{spheroid} can be an ellipsoid vector or spheroid
+## (see help for referenceEllipsoid.m).  If omitted or if an empty string is
+## supplied the WGS84 ellipsoid is taken.
+##
+## @var{X}, @var{Y} and @var{Z} are Earth-Centered Earth Fixed coordinates in
+## meters.  They can be scalars, vectors or matrices but they must all have
+## the same size and dimensions.
+##
+## The default @var{lat} and @var{lon} output is in degrees; specify "radians"
+## for optional last argument @var{angleUnit} to return coordinates in
+## radians.  @var{alt} is always in meters.  The size and dimension(s) of
+## @var{lat}, @var{lon} and @var{alt} are the same as @var{X}, @var{Y}
+## and @var{Z}.
+## 
+## @example
+## Aalborg GPS Centre
+## X =     3426949.39675307
+## Y =     601195.852419885
+## Z =     5327723.99358255
+## lat = 57.02929569; 
+## lon = 9.950248114;
+## h = 56.95; # meters
+##
+## >> [lat, lon, alt] = geodetic2ecef ("", X, Y, Z)
+## lat = 57.029
+## lon = 9.9502
+## alt = 56.95
+## @end example
+## @seealso{geodetic2ecef, referenceEllipsoid}
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9658
+
+function [lat, lon, alt] = ecef2geodetic (varargin)
+
+  ## ip = XYZ offset into varargin
+  ip = 0;
+  if (nargin < 3 || nargin > 5)
+    print_usage ();
+  elseif (nargin == 3)
+    ## Only XYZ input expected
+    spheroid = "wgs84";
+    angleUnit = "degrees";
+  elseif (nargin == 4)
+    if (isnumeric (varargin{4}))
+      ## Assume arg #1 = spheroid
+      angleUnit = "degrees";
+      spheroid = varargin{1};
+      ip = 1;
+    else
+      ## Assume arg #4 = angleunit
+      spheroid = "wgs84";
+      angleUnit = varargin{4};
+    endif
+  elseif (nargin == 5)
+    ip = 1;
+    spheroid = varargin{1};
+    angleUnit = varargin{5};
+  endif
+  X = varargin{ip + 1};
+  Y = varargin{ip + 2};
+  Z = varargin{ip + 3};
+  
+  if (! isnumeric (X) || ! isreal (X) || ...
+      ! isnumeric (Y) || ! isreal (Y) || ...
+      ! isnumeric (Z) || ! isreal (Z))
+    error ("ecef2geodetic.m : numeric input expected");
+  endif
+  
+  if isempty(spheroid)
+    E = wgs84Ellipsoid;
+  else
+    E = referenceEllipsoid (spheroid);
+  endif 
+
+  if (! ischar (angleUnit) || ! ismember (lower (angleUnit(1)), {"d", "r"}))
+    error ("ecef2geodetic.m: angleUnit should be one of 'degrees' or 'radians'")
+  endif
+  
+  if isempty(spheroid)
+    E = wgs84Ellipsoid;
+  else
+    E = referenceEllipsoid (spheroid);
+  endif 
+  
+  ## Insight from: http://wiki.gis.com/wiki/index.php/Geodetic_system
+  lon = atan2 (Y, X);
+  
+  ecc = E.Eccentricity;
+  e_sq = ecc ^ 2;
+  ep_2 = e_sq / (1 - e_sq) ; ## This is (e')^2
+  r = hypot (X, Y);
+  E2 = E.SemimajorAxis ^ 2 - E.SemiminorAxis ^ 2;
+  F = 54 * E.SemiminorAxis .^ 2 * Z .^ 2;
+  G = r .^ 2 + (1 - e_sq) * Z .^ 2 - e_sq * E2;
+  C = (ecc .^ 4 .* F .* r .^ 2) ./ (G .^ 3);
+  S = (1 + C + sqrt (C .^ 2 + 2 .* C)) .^ (1 / 3);
+  P = F ./ (3 .* (S + 1 ./ S + 1) .^ 2 .* G .^ 2);
+  Q = sqrt (1 + 2 * ecc .^ 4 * P);
+  r0 = -(P * e_sq .* r) ./ (1 + Q) + ...
+      sqrt (.5 * E.SemimajorAxis .^ 2 * (1 + 1 ./ Q) - ...
+            (P .* (1 - e_sq) .* Z .^ 2) ./ (Q .^ 2 + Q) - .5 * P .* r .^ 2);
+  U = sqrt ((r - e_sq .* r0) .^ 2 + Z .^ 2);
+  V = sqrt (( r - e_sq .* r0) .^ 2 + (1 - e_sq) .* Z .^ 2);
+  Frac =  E.SemiminorAxis .^ 2  ./ (E.SemimajorAxis * V);
+  Z0 = Frac .* Z;
+  alt = U .* (1 - Frac);
+  lat = atan2 ((Z + ep_2 .* Z0), r) ;
+  
+  if ( strncmpi (lower (angleUnit), "d", 1) == 1 )
+    lon = rad2deg (lon);
+    lat = rad2deg (lat);
+  endif
+  
+endfunction
+
+
+%!shared X, Y, Z
+%! X = 3426949.397;
+%! Y = 601195.852;
+%! Z = 5327723.994; ## meters
+
+%!test
+%! [latd, lond, h] = ecef2geodetic ("wgs84", X, Y, Z);
+%! assert ([latd, lond, h], [57.02929569, 9.950248114, 56.95], 10e-3);
+
+%!test
+%! [latd, lond, h] = ecef2geodetic (X, Y, Z);
+%! assert ([latd, lond, h], [57.02929569, 9.950248114, 56.95], 10e-3);
+
+%!test
+%! latr = deg2rad (57.02929569);
+%! lonr = deg2rad (9.950248114);
+%! [lat, lon, h2] = ecef2geodetic ("wgs84", X, Y, Z, "radians");
+%! assert ([lat, lon, h2], [latr, lonr, 56.95], 10e-3);
+
+%!test
+%! latr = deg2rad (57.02929569);
+%! lonr = deg2rad (9.950248114);
+%! [lat, lon, h2] = ecef2geodetic (X, Y, Z, "radians");
+%! assert ([lat, lon, h2], [latr, lonr, 56.95], 10e-3);
+
+%!error <angleUnit> ecef2geodetic ("", 4500000, 450000, 50000000, "km")
+%!error <angleUnit> ecef2geodetic (4500000, 450000, 50000000, "km")
+%!error <numeric input expected>  ecef2geodetic ("", "A", 450000, 50000000)
+%!error <numeric input expected>  ecef2geodetic ("", 45i, 450000, 50000000)
+%!error <numeric input expected>  ecef2geodetic ("", 4500000, "B", 50000000)
+%!error <numeric input expected>  ecef2geodetic ("", 4500000, 45i, 50000000)
+%!error <numeric input expected>  ecef2geodetic ("", 4500000, 450000, "C")
+%!error <numeric input expected>  ecef2geodetic (4500000, 450000, "C")
+%!error <numeric input expected>  ecef2geodetic ("", 4500000, 450000, 50i)
+%!error <numeric input expected>  ecef2geodetic (4500000, 450000, 50i)
diff --git a/inst/enu2aer.m b/inst/enu2aer.m
new file mode 100644
index 0000000..f47db5f
--- /dev/null
+++ b/inst/enu2aer.m
@@ -0,0 +1,120 @@
+## Copyright (c) 2014-2020 Michael Hirsch, Ph.D.
+## Copyright (c) 2013-2020, Felipe Geremia Nievinski
+## Copyright (C) 2019-2020 Philip Nienhuis
+##
+## Redistribution and use in source and binary forms, with or without 
+## modification, are permitted provided that the following conditions are met:
+## 1. Redistributions of source code must retain the above copyright notice, 
+##    this list of conditions and the following disclaimer.
+## 2. Redistributions in binary form must reproduce the above copyright notice, 
+##    this list of conditions and the following disclaimer in the documentation 
+##    and/or other materials provided with the distribution.
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
+## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
+## THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+## ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
+## LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+## CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
+## SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
+## OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+## WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+## SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{az}, @var{el}, @var{slantrange} =} enu2aer (@var{east}, @var{n}, @var{up})
+## @deftypefnx {Function File} {@var{az}, @var{el}, @var{slantrange} =} enu2aer (@dots{...}, @var{angleUnit})
+## Converts ENU coordinates to azimuth, elevation, slantrange
+##
+## Inputs:
+## @itemize
+## @item
+## @var{east}, @var{n}, @var{up}:  East, North, Up coordinates of test points (meters)
+##
+## @item
+## (Optional) angleUnit: string for angular units ('radians' or 'degrees', 
+## case-insensitive, only first character is significant).
+## Default is 'd': degrees
+## @end itemize
+##
+## Outputs:
+## @itemize
+## @item
+## @var{az}, @var{el}, @var{slantrange}: look angles and distance to point
+## under test (degrees, degrees, meters)
+## @end itemize
+##
+## Example:
+## @example
+## [az, el, slantrange] = enu2aer (186.28, 286.84, 939.69)
+## az =  33.001
+## el =  70.000
+## slantrange = 1000.00
+## @end example
+##
+## With radians
+## @example
+## [az, el, slantrange] = enu2aer (353.55, 353.55, 866.03,"r")
+## az =  0.78540
+## el =  1.0472
+## slantrange =  1000.0
+## @end example
+##
+## @end deftypefn
+
+## Function adapted by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?8377
+
+function [az, el, slantrange] = enu2aer (east, n, up, angleUnit = "degrees")
+  
+  if (nargin < 3 || nargin > 4)
+    print_usage();
+  endif 
+  
+  if (! isnumeric (east)  || ! isreal (east) || ...
+      ! isnumeric (n)     || ! isreal (n) || ...
+      ! isnumeric (up)    || ! isreal (up))
+    error ("enu2aer.m : numeric values expected");
+  endif 
+
+  if (! all (size (east) == size (n)) || ! all (size (n) == size (up)))
+    error ("enu2aer.m: non-matching dimensions of inputs.");
+  endif
+
+  if (! ischar (angleUnit))
+    error ("enu2ear.m: character value expected for 'angleUnit'");
+  elseif (! strncmpi (angleUnit, "degrees", length (angleUnit)) &&
+          ! strncmpi (angleUnit, "radians", length (angleUnit)))
+    error ("enu2aer.m: illegal input for 'angleUnit'");
+  endif
+
+  r = hypot (east, n);
+  slantrange = hypot (r, up);
+  ## Radians
+  el = atan2 (up, r);
+  az = mod (atan2 (east, n), 2 * atan2 (0, -1));
+  
+  if (nargin == 3) 
+    az = rad2deg (az);
+    el = rad2deg (el);
+  endif 
+  
+endfunction
+
+
+%!test
+%! [az, el, slantrange] = enu2aer (186.277521, 286.84222, 939.69262);
+%! assert ([az, el, slantrange], [33, 70, 1e3], 10e-6)
+%! [az, el, slantrange] = enu2aer (186.277521, 286.84222, 939.69262, "rad");
+%! assert ([az, el, slantrange], [0.57595865, 1.221730476, 1e3], 10e-6)
+
+%!error <numeric> enu2aer ("s", 25, 1e3)
+%!error <numeric> enu2aer (3i, 25, 1e3)
+%!error <numeric> enu2aer (33, "s", 1e3)
+%!error <numeric> enu2aer (33, 3i, 1e3)
+%!error <numeric> enu2aer (33, 25, "s")
+%!error <numeric> enu2aer (33, 25, 3i)
+%!error <non-matching> enu2aer ([1 1], [2 2]', [4 5])
+%!error <non-matching> enu2aer ([1 1], [2 2], [4 5 6])
+%!error <illegal> enu2aer (33, 70, 1e3, "f");
+%!error <illegal> enu2aer (33, 70, 1e3, "radianf");
diff --git a/inst/enu2uvw.m b/inst/enu2uvw.m
new file mode 100644
index 0000000..20179a2
--- /dev/null
+++ b/inst/enu2uvw.m
@@ -0,0 +1,100 @@
+## Copyright (C) 2014-2020 Michael Hirsch, Ph.D.
+## Copyright (C) 2013-2020 Felipe Geremia Nievinski
+## Copyright (C) 2019-2020 Philip Nienhuis
+##
+## Redistribution and use in source and binary forms, with or without 
+## modification, are permitted provided that the following conditions are met:
+## 1. Redistributions of source code must retain the above copyright notice, 
+##    this list of conditions and the following disclaimer.
+## 2. Redistributions in binary form must reproduce the above copyright notice, 
+##    this list of conditions and the following disclaimer in the documentation 
+##    and/or other materials provided with the distribution.
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
+## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
+## THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+## ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
+## LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+## CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
+## SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
+## OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+## WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+## SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{u}, @var{v}, @var{w} =} enu2uvw (@var{east}, @var{north}, @var{up}, @var{lat0}, @var{lon0})
+## @deftypefnx {Function File} {@var{u}, @var{v}, @var{w} =} enu2uvw (@var{east}, @var{north}, @var{up}, @var{lat0}, @var{lon0}, @var{angleUnit})
+## Convert ENU coordinates to UVW coordinates.
+##
+## Inputs:
+##
+## @var{east}, @var{north}, @var{up}: East, North, Up: coordinates of point(s)
+## (meters)
+##
+## @var{lat0}, @var{lon0}: geodetic coordinates of observer/reference point
+## (degrees)
+##
+## @var{angleUnit}: string for angular units ('degrees' or 'radians',
+## case-insensitive, first character will suffice).  Default = 'degrees'.
+##
+## Outputs:
+## 
+## @var{u}, @var{v}, @var{w}:  coordinates of point(s) (meters).
+##
+## @end deftypefn
+
+## Function adapted by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?8377
+
+function [u, v, w] = enu2uvw (east, n, up, lat0, lon0, angleUnit = "degrees")
+
+  if (nargin < 5)
+    print_usage ();
+  endif  
+
+  if (! isnumeric (east) || ! isreal (east) || ...
+      ! isnumeric (n)    || ! isreal (n) || ...
+      ! isnumeric (up)   || ! isreal (up) || ...
+      ! isnumeric (lat0) || ! isreal (lat0) || ...
+      ! isnumeric (lon0) || ! isreal (lon0))
+    error ("enu2uvw.m : numeric values expected for first 5 arguments");
+  endif
+  
+  if (! ischar (angleUnit))
+    error ("enu2uvw.m: character value expected for 'angleUnit'");
+  elseif (strncmpi (angleUnit, "degrees", length (angleUnit)))
+    lat0 = deg2rad (lat0);
+    lon0 = deg2rad (lon0);
+  elseif (! strncmpi (angleUnit, "radians", length (angleUnit)))
+    error ("enu2uvw.m: illegal input for 'angleUnit'");
+  endif    
+  
+  t = cos (lat0) * up - sin (lat0) * n;
+  w = sin (lat0) * up + cos (lat0) * n;
+
+  u = cos (lon0) * t - sin (lon0) * east;
+  v = sin (lon0) * t + cos (lon0) * east;
+  
+endfunction
+
+%!test
+%! [u, v, w] = enu2uvw (186.277521, 286.84222, 939.69262, 42, -82, "d"); 
+%! assert ([u, v, w], [254.940936348589, -475.5397947444, 841.942404132992], 10e-6)
+
+%!test
+%! [u, v, w] = enu2uvw (186.277521, 286.84222, 939.69262, ... 
+%!                      0.733038285837618, -1.43116998663535, "r"); 
+%! assert ([u, v, w], [254.940936348589, -475.5397947444, 841.942404132992], 10e-6)
+
+%!error <numeric> enu2uvw("s", 25, 1e3, 0, 0)
+%!error <numeric> enu2uvw(3i, 25, 1e3, 0, 0)
+%!error <numeric> enu2uvw(33, "s", 1e3, 0, 0)
+%!error <numeric> enu2uvw(33, 3i, 1e3, 0, 0)
+%!error <numeric> enu2uvw(33, 25, "s", 0, 0)
+%!error <numeric> enu2uvw(33, 25, 3i, 0, 0)
+%!error <numeric> enu2uvw(33, 25, 1e3, "s", 0)
+%!error <numeric> enu2uvw(33, 25, 1e3, 3i, 0)
+%!error <numeric> enu2uvw(33, 25, 1e3, 0, "s")
+%!error <numeric> enu2uvw(33, 25, 1e3, 0, 3i)
+%!error <illegal> enu2uvw (33, 70, 1e3, 0, 0, "f");
+%!error <illegal> enu2uvw (33, 70, 1e3, 0, 0, "degreef");
diff --git a/inst/extractfield.m b/inst/extractfield.m
index d7afd77..b18aa29 100644
--- a/inst/extractfield.m
+++ b/inst/extractfield.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/flat2ecc.m b/inst/flat2ecc.m
new file mode 100644
index 0000000..c76818f
--- /dev/null
+++ b/inst/flat2ecc.m
@@ -0,0 +1,66 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+##
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+##
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{ecc} =} flat2ecc (@var{flat}) 
+## Return the eccentricity given a flattening
+##
+## Examples:
+##
+## Scalar input:
+## @example
+##    f_earth = 0.0033528;
+##    flat2ecc (f_earth)
+##    => 0.081819
+## @end example
+##
+## Vector input:
+## @example
+##    flat = 0 : .01 : .05;
+##    flat2ecc (flat)
+##    ans =
+##       0.00000   0.14107   0.19900   0.24310   0.28000   0.31225
+## @end example
+##
+## @seealso{ecc2flat}
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9492
+
+function ec = flat2ecc (fl)
+
+  if nargin < 1
+    print_usage ();
+  endif
+
+  if ( ischar ( fl ) )
+    error ("flat2ecc.m: numeric input expected");
+  elseif (any (fl < 0) || any (fl >= 1))
+    error ("flat2ecc.m: flattening must lie in the real interval [0..1)")
+  else
+    ec = sqrt (2 * fl - fl .^ 2);
+  endif
+
+  endfunction
+
+%!test
+%! flat = 0.00335281317793612; 
+%! f_vec = 0:.01:.05;
+%! assert (flat2ecc (flat), 0.0818192214560008, 10^-12 )
+%! assert (flat2ecc (f_vec), [0 , .141067, .198997, .2431049, .28, .31225], 10^-6);
+
+%!error <numeric input expected> flat2ecc ("a")
+%!error <flattening> flat2ecc(1)
diff --git a/inst/fromDegrees.m b/inst/fromDegrees.m
index da04df0..01575b6 100644
--- a/inst/fromDegrees.m
+++ b/inst/fromDegrees.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/fromRadians.m b/inst/fromRadians.m
index 508776d..7725068 100644
--- a/inst/fromRadians.m
+++ b/inst/fromRadians.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/geocentricLatitude.m b/inst/geocentricLatitude.m
new file mode 100644
index 0000000..6f79b14
--- /dev/null
+++ b/inst/geocentricLatitude.m
@@ -0,0 +1,95 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+## 
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+## 
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{psi} =}  geocentricLatitude (@var{phi}, @var{flattening}) 
+## @deftypefnx {Function File} {@var{psi} =}  geocentricLatitude (@var{phi}, @var{flattening}, @var{angleUnit}) 
+## Return geocentric latitude (psi) given geodetic latitude (phi) and flattening.
+##
+## The default input and output is in degrees; use optional third parameter
+## @var{angleUnit} for radians.  @var{phi} can be a scalar, vector, matrix or
+## any ND array.  @var{flattening} must be a scalar value in the interval
+## [0..1).
+##
+## Examples 
+## Scalar input:
+## @example
+## psi = geocentricLatitude (45, 0.0033528)
+## => psi =
+##  44.8076
+## @end example
+##
+## Also can use radians:
+## @example
+## psi = geocentricLatitude (pi/4, 0.0033528, "radians")
+## => psi =
+##  0.78204
+## @end example
+##
+## Vector Input:
+## @example
+## phi = 35:5:45;
+## psi = geocentricLatitude (phi, 0.0033528)
+## => psi =
+##  34.819      39.811      44.808
+## @end example
+##
+## @seealso{parametricLatitude, geodeticLatitudeFromGeocentric, geodeticLatitudeFromParametric} 
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9640
+
+function psi = geocentricLatitude (phi, flattening, angleUnit="degrees")
+
+  if (nargin < 2 || isempty (angleUnit))
+    print_usage ();
+  endif
+  
+  if (! isnumeric (phi) || ! isreal (phi) || ...
+      ! isnumeric (flattening) || ! isreal (flattening))
+    error ("geocentricLatitude: numeric input expected for args #1 and #2");
+  elseif (! isscalar (flattening))
+    error ("geocentricLatitude: scalar value expected for flattening");
+  elseif (flattening < 0 || flattening >= 1)
+    error ("geocentricLatitude: flattening must lie in the real interval [0..1)" )
+  elseif (! ischar (angleUnit) || ! ismember (lower (angleUnit(1)), {"d", "r"}))
+    error ("geocentricLatitude: angleUnit should be one of 'degrees' or 'radians'");
+  endif
+
+  ## Make sure phi and (later on) flattening are element-wise conformant
+  if (strncmpi (angleUnit, "r", 1) == 1)
+    ## Insight From: Fundamentals of Astrodynamics and Applications,
+    ## (David Vallado 3rd edition pg 148)
+    psi = atan ((1 - flattening)^2 * tan (phi));
+  else
+    psi = atand ((1 - flattening)^2 * tand (phi));
+  end
+  
+endfunction
+
+
+%!test
+%! earth_flattening = 0.0033528;
+%! assert (geocentricLatitude (45, earth_flattening), 44.8075766, 10e-6);
+%! assert (geocentricLatitude (pi/4, earth_flattening, 'radians'), 0.78204, 10e-6);
+
+%!error <numeric input expected> geocentricLatitude (0.5, "flat")
+%!error <numeric input expected> geocentricLatitude (0.5, 5i)
+%!error <numeric input expected> geocentricLatitude ("phi", 0.0033528)
+%!error <numeric input expected> geocentricLatitude (5i, 0.0033528 )
+%!error <scalar value expected> geocentricLatitude ([45 50], [0.7 0.8])
+%!error <flattening must lie> geocentricLatitude (45, 1)
+%!error <angleUnit> geocentricLatitude (45, 0.0033528, "km")
diff --git a/inst/geodetic2ecef.m b/inst/geodetic2ecef.m
new file mode 100644
index 0000000..62df15c
--- /dev/null
+++ b/inst/geodetic2ecef.m
@@ -0,0 +1,152 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+## 
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+## 
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{X}, @var{Y}, @var{Z} =} geodetic2ecef (@var{lat}, @var{lon}, @var{alt})
+## @deftypefnx {Function File} {@var{X}, @var{Y}, @var{Z} =} geodetic2ecef (@var{spheroid}, @var{lat}, @var{lon}, @var{alt})
+## @deftypefnx {Function File} {@var{X}, @var{Y}, @var{Z} =} geodetic2ecef (@dots{}, @var{angleUnit})
+## @deftypefnx {Function File} {@var{X}, @var{Y}, @var{Z} =} geodetic2ecef (@var{lat}, @var{lon}, @var{alt}, @var{spheroid})
+## Converts from geodetic coordinate frame to ECEF coordinate frame.
+##
+## @var{lat}, @var{lon} and @var{alt} (latitude, longitude and height,
+## respectively) can each be scalars, vectors or matrices but must all have
+## the exact same size and dimension(s).
+##
+## @var{spheroid} ia user-specified sheroid (see referenceEllipsoid); it can
+## be omitted or given as an ampty string, in which cases WGS84 will be the
+## default spheroid.
+##
+## @var{angleUnit} can be "degrees" (= default) or "radians".  In the last
+## calling fom, with @var{spheroid} as 4th input argument, @var{angleUnit}
+## is in degrees and cannot be changed.
+##
+## The output arguments @var{X}, @var{Y}, @var{Z} (Earth-Centered Earth
+## Fixed coordinates) are in meters and have the same sizes and dimensions
+## as input arguments @var{lat}, @var{lon} and @var{alt}.
+## 
+## @example
+## Aalborg GPS Centre
+## lat=57.02929569; 
+## lon=9.950248114;
+## h= 56.95; # meters
+## >> [X, Y, Z] = geodetic2ecef ("", lat, lon, h)
+## X =     3426949.39675307
+## Y =     601195.852419885
+## Z =     5327723.99358255
+## @end example
+## @seealso{ecef2geodetic}
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9658
+
+function [X, Y, Z] = geodetic2ecef (varargin)
+
+  ip = 0;
+  spheroid = "";
+  angleUnit = "degrees";
+  if (nargin < 3 || nargin > 5)
+    print_usage ();
+  elseif (nargin == 3)
+    ## Assume just Lat, Lon and Alt given
+  elseif (nargin == 4)
+    if (isnumeric (varargin{1}))
+      ## Find out if arg #4 = angleunit or spheroid
+      if (isnumeric (varargin{4}))
+        ## Spheroid
+        spheroid = varargin{4};
+      elseif (ischar (varargin{4}))
+        if (ismember (varargin{4}(1), {"r", "d"}))
+          angleUnit = varargin{4};
+        else
+          spheroid = varargin{4};
+        endif
+      else
+        error ("geodetic3ecef.m: spheroid or angleutin expected for arg. #4");
+      endif
+    else
+      ip = 1;
+      spheroid = varargin{1};
+    endif
+  elseif (nargin == 5)
+    ip = 1;
+    spheroid = varargin{1};
+    angleUnit = varargin{5};
+  endif
+  lat = varargin{ip + 1};
+  lon = varargin{ip + 2};
+  alt = varargin{ip + 3};
+
+  if (! isnumeric (lat) || ! isreal (lat) || ...
+      ! isnumeric (lon) || ! isreal (lon) || ...
+      ! isnumeric (alt) || ! isreal (alt))
+    error ("geodetic2ecef.m : numeric input expected");
+  endif
+
+  if (! ischar (angleUnit) || ! ismember (lower (angleUnit(1)), {"d", "r"}))
+    error ("geodetic2ecef.m: angleUnit should be one of 'degrees' or 'radians'")
+  endif
+
+  if (isempty (spheroid))
+    E = wgs84Ellipsoid;
+  else
+    E = referenceEllipsoid (spheroid);
+  endif
+
+  if (strncmpi (lower (angleUnit), "r", 1) == 1)
+    c_p = cos (lat);
+    s_p = sin (lat);
+
+    c_l = cos (lon);
+    s_l = sin (lon);
+  else 
+    c_p = cosd (lat);
+    s_p = sind (lat);
+    
+    c_l = cosd (lon);
+    s_l = sind (lon);
+  endif
+
+
+  #Insight From: Algorithms for Global Positioning pg 42
+  N = E.SemimajorAxis ./ sqrt (1 - E.Eccentricity ^ 2 * s_p .^ 2);
+  X = (N + alt) .* (c_p .* c_l) ; 
+  Y = (N + alt) .* (c_p .* s_l) ; 
+  Z = (N .* (1 - E.Flattening) ^ 2  + alt) .* s_p;
+
+endfunction
+
+
+%!test
+%!shared h
+%! latd = 57.02929569;
+%! lond = 9.950248114;
+%! h = 56.95; ## meters
+%! [x, y, z]=geodetic2ecef("wgs84", latd, lond, h);
+%! assert ([x, y, z], [3426949.397, 601195.852, 5327723.994], 10e-3);
+
+%!test
+%! lat = deg2rad (57.02929569);
+%! lon = deg2rad (9.950248114);
+%! [x2, y2, z2] = geodetic2ecef ("wgs84", lat, lon, h, "radians");
+%! assert ([x2, y2, z2], [3426949.397, 601195.852, 5327723.994], 10e-3);
+
+%!error <angleUnit> geodetic2ecef ("", 45, 45, 50, "km")
+%!error <numeric input expected>  geodetic2ecef ("", "A", 45, 50)
+%!error <numeric input expected>  geodetic2ecef ("", 45i, 45, 50)
+%!error <numeric input expected>  geodetic2ecef ("", 45, "B", 50)
+%!error <numeric input expected>  geodetic2ecef ("", 45, 45i, 50)
+%!error <numeric input expected>  geodetic2ecef ("", 45, 45, "C")
+%!error <numeric input expected>  geodetic2ecef ("", 45, 45, 50i)
\ No newline at end of file
diff --git a/inst/geodeticLatitudeFromGeocentric.m b/inst/geodeticLatitudeFromGeocentric.m
new file mode 100644
index 0000000..ca030f0
--- /dev/null
+++ b/inst/geodeticLatitudeFromGeocentric.m
@@ -0,0 +1,92 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+## 
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+## 
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{phi} =}  geodeticLatitudeFromGeocentric (@var{psi}, @var{flattening}) 
+## @deftypefnx {Function File} {@var{phi} =}  geodeticLatitudeFromGeocentric (@var{psi}, @var{flattening}, @var{angleUnit}) 
+## Return geodetic latitude (phi) given geocentric latitude (psi) and flattening.
+##
+## The default input and output is in degrees; use optional third parameter
+## @var{angleUnit} for radians.  @var{psi} can be a scalar, vector, matrix or
+## any ND array.  @var{flattening} must be a scalar value in the interval
+## [0..1).
+##
+## Examples 
+## Scalar input:
+## @example
+## phi = geodeticLatitudeFromGeocentric (45, 0.0033528)
+## => phi =
+##   45.192
+## @end example
+##
+## Also can use radians:
+## @example
+## phi = geodeticLatitudeFromGeocentric (pi/4, 0.0033528, "radians")
+## => phi =
+##  0.78876
+## @end example
+##
+## Vector Input:
+## @example
+## psi = 35:5:45;
+## phi = geodeticLatitudeFromGeocentric (psi, 0.0033528)
+## => phi =
+##  35.181       40.19      45.192
+## @end example
+##
+## @seealso{geocentricLatitude, geodeticLatitudeFromGeocentric, parametricLatitude} 
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9640
+
+function phi = geodeticLatitudeFromGeocentric (psi, flattening, angleUnit="degrees")
+
+  if (nargin < 2 || isempty (angleUnit))
+    print_usage ();
+  endif
+  
+  if (! isnumeric (psi) || ! isreal (psi) || ...
+      ! isnumeric (flattening) || ! isreal (flattening))
+    error ("geodeticLatitudeFromGeocentric: numeric input expected");
+  elseif (! isscalar (flattening))
+    error ("geodeticLatitudeFromGeocentric: scalar value expected for flattening");
+  elseif (flattening < 0 || flattening >= 1)
+    error ( "geodeticLatitudeFromGeocentric.m: flattening must lie in the real interval [0..1)" )
+  elseif (! ischar (angleUnit) ||! ismember (lower (angleUnit(1)), {"d", "r"}))
+    error ("geodeticLatitudeFromGeocentric: angleUnit should be one of 'degrees' or 'radians'");
+  endif
+
+  if (strncmpi (angleUnit, "r", 1) == 1)
+    phi = atan2 (tan (psi), (1 - flattening) ^ 2);
+  else 
+    phi = atan2d (tand (psi), (1 - flattening) ^ 2);
+  endif 
+
+endfunction
+
+
+%!test
+%! earth_flattening = 0.0033528;
+%! assert (geodeticLatitudeFromGeocentric (45, earth_flattening), 45.1924226, 10e-6);
+%! assert (geodeticLatitudeFromGeocentric (pi/4, earth_flattening, 'radians'), 0.78876, 10e-6);
+
+%!error <numeric input expected> geodeticLatitudeFromGeocentric (0.5, "flat")
+%!error <numeric input expected> geodeticLatitudeFromGeocentric (0.5, 5i )
+%!error <numeric input expected> geodeticLatitudeFromGeocentric ("psi", 0.0033528)
+%!error <numeric input expected> geodeticLatitudeFromGeocentric (5i, 0.0033528 )
+%!error <scalar value expected> geodeticLatitudeFromGeocentric ([45 50], [0.7 0.8])
+%!error <flattening must lie> geodeticLatitudeFromGeocentric (45, 1)
+%!error <angleUnit> geodeticLatitudeFromGeocentric (45, 0.0033528 ,"km")
diff --git a/inst/geodeticLatitudeFromParametric.m b/inst/geodeticLatitudeFromParametric.m
new file mode 100644
index 0000000..ef7203f
--- /dev/null
+++ b/inst/geodeticLatitudeFromParametric.m
@@ -0,0 +1,92 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+## 
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+## 
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{phi} =} geodeticLatitudeFromParametric (@var{beta}, @var{flattening}) 
+## @deftypefnx {Function File} {@var{phi} =} geodeticLatitudeFromParametric (@var{beta}, @var{flattening}, @var{angleUnit}) 
+## Returns geodetic latitude (phi) given parametric latitude and flattening.
+##
+## Parametric latitude (@var{beta}) is also known as a reduced latitude.
+## The default input and output is in degrees; use optional third parameter
+## @var{angleUnit} for radians.  @var{beta} can be a scalar, vector, matrix
+## or any ND array.  @var{flattening} must be a scalar value in the interval
+## [0..1).
+##
+## Examples:
+## Scalar input:
+## @example
+## phi = geodeticLatitudeFromParametric (45, 0.0033528)
+## => phi =
+##  45.096
+## @end example
+##
+## Also can use radians:
+## @example
+## phi = geodeticLatitudeFromParametric (pi/4, 0.0033528, "radians")
+## => phi =
+##  0.78708
+## @end example
+##
+## Vector Input:
+## @example
+## beta = 35:5:45;
+## phi = geodeticLatitudeFromParametric (beta, 0.0033528)
+## => phi =
+##  35.09      40.095      45.096
+## @end example
+##
+## @seealso{geocentricLatitude, geodeticLatitudeFromGeocentric, parametricLatitude} 
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9640
+
+function phi = geodeticLatitudeFromParametric (beta, flattening, angleUnit="degrees")
+  
+  if (nargin < 2)
+    print_usage ();
+  endif
+
+  if (! isnumeric (beta) || ! isreal (beta) || ...
+      ! isnumeric (flattening) || ! isreal (flattening))
+    error ("geodeticLatitudeFromParametric : numeric input expected");
+  elseif (! isscalar (flattening))
+    error ("geodeticLatitudeFromParametric: scalar value expected for flattening");
+  elseif (flattening < 0 || flattening >= 1)
+    error ("geodeticLatitudeFromParametric: flattening must lie in the real interval [0..1)" );
+  elseif (! ischar (angleUnit) ||! ismember (lower (angleUnit(1)), {"d", "r"}))
+    error ("geodeticLatitudeFromParametric: angleUnit should be one of 'degrees' or 'radians'");
+  endif
+
+  if (strncmpi (angleUnit, "r", 1) == 1)
+    phi = atan2 (tan (beta), (1 - flattening)) ;
+  else 
+    phi = atan2d (tand (beta), (1 - flattening)) ;
+  endif
+  
+endfunction
+
+%!test
+%! earth_flattening  =  0.0033528 ;
+%! assert ( geodeticLatitudeFromParametric (45, earth_flattening), 45.0962122, 10e-6);
+%! assert ( geodeticLatitudeFromParametric (pi/4, earth_flattening, 'radians'), 0.78708, 10e-6);
+
+%!error <numeric input expected> geodeticLatitudeFromParametric (0.5, "flat")
+%!error <numeric input expected> geodeticLatitudeFromParametric (0.5, 5i)
+%!error <numeric input expected> geodeticLatitudeFromParametric ("beta", 0.0033528)
+%!error <numeric input expected> geodeticLatitudeFromParametric (5i, 0.0033528 )
+%!error <scalar value expected> geodeticLatitudeFromParametric ([45 50], [0.7 0.8])
+%!error <flattening must lie> geodeticLatitudeFromParametric (45, 1)
+%!error <angleUnit> geodeticLatitudeFromParametric (45, 0.0033528, "km")
diff --git a/inst/geoshow.m b/inst/geoshow.m
index 8ca676f..b851a99 100644
--- a/inst/geoshow.m
+++ b/inst/geoshow.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Philip Nienhuis
+## Copyright (C) 2014-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/gmlread.m b/inst/gmlread.m
new file mode 100644
index 0000000..6f3308c
--- /dev/null
+++ b/inst/gmlread.m
@@ -0,0 +1,263 @@
+## Copyright (C) 2017-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} {@var{gml} =} gmlread (@var{fname}, @var{dots})
+## Read a .gml (Geographic Markup Language) file.
+##
+## gmlread only reads coordinates, no attributes.
+##
+## Required input argument @var{fname} is the name of a .gml file.  If
+## no other arguments are specified all features in the entire .gml file
+## will be read.
+##
+## The following optional property/value pairs (all case-insensitive)
+## can be specified to select only some feature types and/or features
+## limited to a certain area:
+##
+## @itemize
+## @item "FeatureType"
+## (Just one "f" will do)  Only read a certain feature type; the value
+## can be one of "Points", "LineStrings" or "Polygons" (only the first
+## three characters matter).  Multiple feature types can be selected by
+## specifying multiple FeatureType property/value pairs.
+## @end item
+##
+## @item BoundingBox
+## (just one "b" suffices)  Only read features that lie entirely within
+## a coordinate rectangle specified as a 2x2 matrix containing [minX minY;
+## maxX maxY].
+## @end item
+## @end itemize
+##
+## In addition verbose output can be obtained by specifying the following
+## property/value pair:
+##
+## @itemize
+## @item Debug
+## (a "d" will do)  followed by a numeric value of 1 (or true) specifies
+## verbose output; a numeric value of 0 (or false) suppresses verbose output.
+## @end item
+## @end itemize
+##
+## The output of gmlread comprises a struct containing up to three
+## mapstructs (MultiPoint and/or Polyline and/or Polygon mapstructs),
+## depending on optional featuretype selection.
+##
+## @seealso{shaperead}
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2017-03-06
+
+function [gml] = gmlread (fname, varargin)
+
+  ## FIXME Input validation
+  fid = fopen (fname, "r");
+  if (fid < 0)
+    error ("gmlread: file %s not found.\n", fname);
+  endif
+
+  ## Process [property, value] options
+  idx = pol = [];
+  dbug = feat = ipt = iln = ipg = 0;
+  for ii=1:2:numel (varargin)
+    if (ischar (varargin{ii}) && numel (varargin{ii}) > 0 && mod (numel (varargin), 2) == 0)
+      switch lower (varargin{ii})(1)
+        case "f"
+          ## Feature type. Keep track of whether this option was entered
+          feat = 1;
+          if (ischar (varargin{ii+1}))
+            switch lower (varargin{ii+1})(1:3)
+              case "poi"
+                ipt = 1;
+              case "lin"
+                iln = 1;
+              case "pol"
+                ipg = 1;
+              otherwise
+                error ("gmlread: unknown FeatureType '%s'", varargin{ii+1});
+            endswitch
+          else
+            error ("gmlread: illegal value for argument %d\n", ii+1);
+          endif
+        case "b"
+          ## Bounding box
+          bbox = varargin{ii+1};
+          if (! isnumeric (idx) && size (bbox, 1) != 2 && size (bbox, 2) != 2)
+            error ("gmlread: numeric 2x2 matrix expected for arg.# %d\n", ii+1);
+          else
+            pol = [bbox(1, 1), bbox(2, 1), bbox(2, 1), bbox(1, 1), bbox(1, 1); ...
+                   bbox(1, 2), bbox(1, 2), bbox(2, 2), bbox(2, 2), bbox(1, 2)];
+          endif
+        case ("d")
+          ## Debug
+          dbug = varargin{ii+1} == 1;
+        otherwise
+          warning ("gmlread: unknown option '%s' - ignored\n", varargin{ii});
+      endswitch
+    else
+      error ("gmlread: wrong [property, value] options list");
+    endif
+  endfor
+  if (! feat)
+    ipt = iln = ipg = 1;
+  endif
+
+  if (dbug)
+    printf ("Reading %s ... ", fname);
+  endif
+  xml = fread (fid, 1000, "char=>char")';
+
+  ## Skip header lines/-nodes
+  hdls = cell2mat (regexp (xml, '(<\?.*?\?>)|(<!.*?>)', "tokenExtents"));
+  spos = hdls(end);
+  ## Start with outer content node
+  fseek (fid, spos+1, "bof");
+  xml = fread (fid, Inf, "char=>char")';
+  fclose (fid);
+
+  ## Parse xml int 5xN cell array
+  ptrn = '<gml:((Point|LineString|Polygon)) .*?<gml:(coordinates|posList|pos).*?srsDimension="(\d)".*?>([\d\. ]*?)</gml:(coordinates|posList|pos)>';
+  feats = reshape (cell2mat (regexp (xml, ptrn, "tokens")), 5, []);
+
+  if (ipt)
+    if (dbug)
+      printf ("\nSearching Points ... ");
+    endif
+    ipt = find (strcmp (feats(1, :), "Point"));
+    if (dbug)
+      printf ("%d found.\n", numel (ipt));
+    endif
+  else
+    ipt = [];
+  endif
+
+  if (iln)
+    if (dbug)
+      printf ("Searching LineStrings ... ");
+    endif
+    iln = find (strcmp (feats(1, :), "LineString"));
+    if (dbug)
+      printf ("%d found.\n", numel (iln));
+    endif
+  else
+    iln = [];
+  endif
+
+  if (ipg)
+    if (dbug)
+      printf ("Searching Polygons ... ");
+    endif
+    ipg = find (strcmp (feats(1, :), "Polygon"));
+    if (dbug)
+      printf ("%d found.\n", numel (ipg));
+    endif
+  else
+    ipg = [];
+  endif
+
+  if (dbug)
+    printf ("Converting ....\n", numel (ipg));
+  endif
+
+  ## Points
+  if (! isempty (ipt))
+    gmlpt = repmat (struct ("Geometry", "Multipoint", "X", NaN (1, 10), "Y",
+                            NaN (1, 10), "BoundingBox", NaN (2, 2)), numel (ipt), 1);
+    jpt = 0;
+    for ii=1:numel (ipt)
+      if (dbug)
+        printf ("%d of %d Points ....\r", ii, numel (ipt));
+      endif
+      [xy, cnt] = sscanf (feats{4, ipt(ii)}, "%f");
+      dimsn = str2double (feats{3, ipt(ii)});
+      xy = reshape (xy, dimsn, []);
+      if (isempty (pol) || bbox <= 0 || all (inpolygon (xy(1, :), xy(2, :), pol(1, :), pol(2, :))))
+        ++jpt;
+        gmlpt(jpt).X = xy(1, :);
+        gmlpt(jpt).Y = xy(2, :);
+        gmlpt(jpt).BoundingBox = [min(xy(1, :)), min(xy(2, :)); max(xy(1, :)), max(xy(2, :))];
+        if (dimsn >= 3)
+          gmlpt(jpt).Z = xy(3, :);
+          gmlpt(jpt).BoundingBox = [gmlpt(jpt).BoundingBox, [min(xy(3, :)); max(xy(3, :))]];
+        endif
+      endif
+    endfor
+    if (dbug)
+      printf ("\n");
+    endif
+    gml.Points = gmlpt(1:jpt);
+  endif
+
+  ## LineStrings
+  if (! isempty (iln))
+    jpt = 0;
+    gmlpl = repmat (struct ("Geometry", "Polyline", "X", NaN (1, 15), "Y",
+                            NaN (1, 15), "BoundingBox", NaN (2, 2)), numel (iln), 1);
+    for ii=1:numel (iln)
+      if (dbug)
+        printf ("%d of %d LineStrings ....\r", ii, numel (iln));
+      endif
+      [xy, cnt] = sscanf (feats{4, iln(ii)}, "%f");
+      dimsn = str2double (feats{3, iln(ii)});
+      xy = reshape (xy, dimsn, []);
+      if (isempty (pol) || all (inpolygon (xy(1, :), xy(2, :), pol(1, :), pol(2, :))))
+        ++jpt;
+        gmlpl(jpt).X = xy(1, :);
+        gmlpl(jpt).Y = xy(2, :);
+        gmlpl(jpt).BoundingBox = [min(xy(1, :)), min(xy(2, :)); max(xy(1, :)), max(xy(2, :))];
+        if (dimsn >= 3)
+          gmlpl(jpt).Z = xy(3, :);
+          gmlpl(jpt).BoundingBox = [gmlpl(jpt).BoundingBox, [min(xy(3, :)); max(xy(3, :))]];
+        endif
+      endif
+    endfor
+    if (dbug)
+      printf ("\n");
+    endif
+    gml.Polylines = gmlpl(1:jpt);
+  endif
+
+  ## Polygons
+  if (! isempty (ipg))
+    jpt = 0;
+    gmlpg = repmat (struct ("Geometry", "Polygon", "X", NaN (1, 20), "Y",
+                            NaN (1, 20), "BoundingBox", NaN (2, 2)), numel (ipg), 1);
+    for ii=1:numel (ipg)
+      if (dbug)
+        printf ("%d of %d Polygons ....\r", ii, numel (ipg));
+      endif
+      [xy, cnt] = sscanf (feats{4, ipg(ii)}, "%f");
+      dimsn = str2double (feats{3, ipg(ii)});
+      xy = reshape (xy, dimsn, []);
+      if (isempty (pol) || all (inpolygon (xy(1, :), xy(2, :), pol(1, :), pol(2, :))))
+        ++jpt;
+        gmlpg(jpt).X = xy(1, :);
+        gmlpg(jpt).Y = xy(2, :);
+        gmlpg(jpt).BoundingBox = [min(xy(1, :)), min(xy(2, :)); max(xy(1, :)), max(xy(2, :))];
+        if (dimsn >= 3)
+          gmlpg(jpt).Z = xy(3, :);
+          gmlpg(jpt).BoundingBox = [gmlpg(jpt).BoundingBox, [min(xy(3, :)); max(xy(3, :))]];
+        endif
+      endif
+    endfor
+    if (dbug)
+      printf ("\n");
+    endif
+    gml.Polygons = gmlpg(1:jpt);
+  endif
+
+endfunction
diff --git a/inst/gpxread.m b/inst/gpxread.m
new file mode 100644
index 0000000..2eec30f
--- /dev/null
+++ b/inst/gpxread.m
@@ -0,0 +1,264 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} {@var{out} =} gpxread (@var{fname})
+## @deftypefnx {} {@var{out} =} gpxread (@var{fname}, @dots{})
+## Read data from a gpx file.
+##
+## Input argument @var{fname} (a character string) can be a valid file
+## name or a valid URL.
+##
+## If no other input arguments are given gpxread will read all data in
+## @var{fname} into one output struct @var{out}.  The data to be read can
+## be selected and/or limited by specifying one or more of the following
+## optional property/value pairs (all case-insensitive):
+##
+## @itemize
+## @item "FeatureType'
+## This option (a mere "f" suffices) can be one of:
+## @table @asis
+## @item
+## "WayPoint or simply "w": Read waypoints.
+## @end item
+##
+## @item
+## "Track" or "t": read tracks.
+## @end item
+##
+## @item
+## "Route" or "t": read routes.
+## @end item
+##
+## @item
+## "Auto" or "a" (default value): read all data.
+## @end item
+## @end table
+##
+## Multiple FeatureType property/value pairs can be specified.
+## @end item
+##
+## @item "Index"
+## The ensuing Index value should be a numeric value, or numeric vector,
+## of indices of the features to be read.
+## @end item
+## @end itemize
+##  
+## Output argument @var{out} is a struct array with field names Name,
+## Lat, Lon, Ele, Time, and -in case of routes- Names.  "Name" refers
+## to the name of the waypoints, tracks or routes that have been read.
+## "Lat", "Lon" and "Ele" refer to the latitude, longitude and elevation
+## of the various features, in case of tracks field "Time" refers to
+## the time of the trackpoint.  In case of tracks and routes these are
+## vectors, each element corresponding to one track point.  For each
+## individual track multiple track segments are separated by NaNs.  For
+## routes the field "Names" contains a cell array holding the names of
+## the individual route points.
+##
+## Examples:
+##
+## @example
+##   A = gpxread ("trip2.gpx", "feature", "track", "index", 2);
+##   (which returns data from the second track in file "trip1.gpx")
+## @end example
+##
+## @example
+##   B = gpxread ("trip2.gpx", "f", "t", "f", "r");
+##   (which returns track and route data from file "trip2.gpx")
+## @end example
+##
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2017-02-05
+
+function [outp] = gpxread (fname, varargin)
+
+  ## Input validation
+  if (nargin < 1)
+    print_usage ();
+  elseif (! ischar (fname))
+    error ("gpread: file name expected for arg 1\n");
+  elseif (! isempty (cell2mat (cell2mat ...
+           (regexp (fname, '(ftp://|http://|file://)', "tokens")))))
+    url = true;
+  else
+    [pth, fnm, ext] = fileparts (fname);
+    if (isempty (ext))
+      fname = [fname ".gpx"];
+    endif
+    url = false;
+  endif
+
+  if (nargin < 2)
+    gtr = grt = gpt = 1;
+  else
+    gtr = grt = gpt = 0;
+  endif
+
+  if (mod (nargin, 2) != 1)
+    error ("gpxread: insufficient nr. of input arguments\n");
+  endif
+
+  idx = [];
+  for ii=1:2:numel (varargin)
+    if (ischar (varargin{ii}) && numel (varargin{ii}) > 0)
+      switch lower (varargin{ii})(1)
+        case "f"
+          switch lower (varargin{ii+1})(1)
+            case "t"
+              gtr = 1;
+            case "r"
+              grt = 1;
+            case "w"
+              gpt = 1;
+            case "a"
+              gtr = grt = gpt = 1;
+            otherwise
+              error ("gpxread: unknown FeatureType '%s'", varargin{ii+1});
+            endswitch
+        case "i"
+          idx = varargin{ii+1};
+          if (! isnumeric (idx))
+            error ("gpxread: numeric value or vector expected for arg.# %d\n", ii+1);
+          else
+            idx = uint32 (idx);
+          endif
+        otherwise
+          warning ("gpxread: unknown option '%s' - ignored\n", varargin{ii});
+      endswitch
+    else
+      error ("gpxread: wrong argument type for arg. %d - 'FeatureType' or \
+'Index' expected", ii+1);
+    endif
+  endfor
+
+  if (url)
+    ## Untested
+    xml = urlread (fname);
+  else
+    fid = fopen (fname, "r");
+    if (fid < 0)
+      error ("gpxread: couldn't open file %s\n", fname);
+    endif
+    xml = fread (fid, Inf, "char=>char")';
+    fclose (fid);
+  endif
+
+  outp = repmat (struct ("Type", "-", ...
+                         "Lat",  [],  ...
+                         "Lon",  [],  ...
+                         "Ele",  [],  ...
+                         "Time", [],  ...
+                         "Name", "-"), 0, 1);
+
+  if (gpt)
+    ## (Try to) Read waypoints
+    ptrnp = 'wpt lat="(.*?)" lon="(.*?)">.*?ele>(.*?)</ele.*?name>(.*?)</name';
+    wpts = reshape (cell2mat ( regexp (xml, ptrnp, "tokens")'), [], 4);
+    if (! isempty (wpts))
+      wpts(:, 1:3) = num2cell (str2double (wpts(:, 1:3)));
+      if (isempty (idx))
+        idx = [1:size(wpts, 1)]';
+      else
+        idx(idx < 1) = [];
+        idx(idx > size (wpts, 1)) = [];
+      endif
+      [outp(1:numel (idx)).Name] = deal (wpts(idx, 4){:});
+      [outp(1:numel (idx)).Type] = deal ("WayPoint");
+      [outp(1:numel (idx)).Lat] = deal (wpts(idx, 1){:});
+      [outp(1:numel (idx)).Lon] = deal (wpts(idx, 2){:});
+      [outp(1:numel (idx)).Ele] = deal (wpts(idx, 3){:});
+    endif
+  endif
+
+  if (gtr)
+    ## Read tracks
+    ptrnt1A = '<trkpt lat="(.*?)" lon="(.*?)".*?ele>(.*?)</ele>.*?<time>(.*?)</time';
+    ptrnt1B = '<trkpt lat="(.*?)" lon="(.*?)".*?time>(.*?)</time.*?ele>(.*?)</ele>';
+    ptrnt2 = '<trkpt lat="(.*?)" lon="(.*?)".*?ele>(.*?)</ele';
+    [trk, ~, is] = getxmlnode (xml, "trk", 1, 1);
+    itr = 0;
+    if (is != 0)
+      do
+        if (isempty (idx) || ismember (++itr, idx))
+          [trkseg, ~, ist] = getxmlnode (trk, "trkseg", 1, 1);
+          if (ist != 0)
+            outp(end+1).Type = "Track";
+            outp(end).Name = getxmlnode (trk, "name", 1, 1);
+            ## Check if tracks have time node
+            it = index (trkseg, "</time>", "first");
+            ## Check ele/time node order
+            if (it)
+              if (index (trkseg, "</ele>", "first") < it)
+                ptrnt = ptrnt1A;
+                dcol = 4;
+              else
+                ptrnt = ptrnt1B;
+                dcol = 3;
+              endif
+              ncols = 4;
+            else
+              ptrnt = ptrnt2;
+              ncols = 3;
+            endif
+            out = NaN (0, ncols);
+            do
+              arr = reshape (cell2mat (regexp (trkseg, ptrnt, "tokens")), ncols, [])';
+              if (ncols == 4)
+                arr = [ (str2double (arr(:, [1:2 7-dcol]))) (datenum (arr(:, dcol), "yyyy-mm-ddTHH:MM:SSZ")) ];
+              else
+                arr = str2double (arr);
+              endif
+              out = [out; arr; NaN(1, ncols)];
+              [trkseg, ~, ist] = getxmlnode (trk, "trkseg", ist, 1);
+            until (ist == 0);
+            out(end, :) = [];
+            outp(end).Lat = out(:, 1);
+            outp(end).Lon = out(:, 2);
+            outp(end).Ele = out(:, 3);
+            if (ncols == 4)
+              outp(end).Time = out(:, 4);
+            endif
+          endif
+        endif
+        [trk, ~, is] = getxmlnode (xml, "trk", is, 1);
+      until (is == 0);
+    endif
+  endif
+
+  if (grt)
+    ## Read routes
+    ptrnr = 'rtept lat="(.*?)" lon="(.*?)".*?ele>(.*?)</ele.*?name>(.*?)</name';
+    [rte, ~, is] = getxmlnode (xml, "rte", 1, 1);
+    irt = 0;
+    if (is != 0)
+      do
+        if (isempty (idx) || ismember (++irt, idx))
+          outp(end+1).Type = "Route";
+          outp(end).Name = getxmlnode (rte, "name", 1, 1);
+          [rteseg, ~, isr] = getxmlnode (rte, "rtept", 1, 1);
+          rtp = reshape (cell2mat ( regexp (rte, ptrnr, "tokens")'), [], 4);
+          [outp(end).Lat] = str2double (rtp(:, 1));
+          [outp(end).Lon] = str2double (rtp(:, 2));
+          [outp(end).Ele] = str2double (rtp(:, 3));
+          [outp(end).Names] = rtp(:, 4);
+        endif
+       [rte, ~, is] = getxmlnode (xml, "rte", is, 1);
+      until (is == 0);
+    endif
+  endif
+  
+endfunction
diff --git a/inst/isShapeMultipart.m b/inst/isShapeMultipart.m
new file mode 100644
index 0000000..3db52d3
--- /dev/null
+++ b/inst/isShapeMultipart.m
@@ -0,0 +1,72 @@
+## Copyright (C) 2016-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {} {@var{mp} =} isShapeMultipart (@var{x}, @var{y})
+## Checks if a polygon or polyline consists of multiple parts separated by
+## NaN rows.
+##
+## @var{x} and @var{y} must be vectors with the same orientation (either
+## row vectors of column vectors).
+##
+## Output argument @var{mp} is zero (false) if the shape contains no NaN
+## rows, otherwise it equals the number of polygon/polyline shape parts.
+##
+## @seealso{}
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2016-05-22
+
+function mp = isShapeMultipart (x, y)
+
+  if (nargin  < 2)
+    print_usage ();
+  endif
+  if (isrow (x) != isrow (y))
+    error ("isShapeMultipart: x and y must be both row vectors or both column vectors")
+  endif
+  if (numel (x) != numel (y))
+    error ("isShapeMultipart: incompatible input vectors");
+  endif
+
+  mp = 0;
+  mp_x = find (isnan (x));
+  mp_y = find (isnan (y));
+  if (! isempty (mp_x) && ! isempty (mp_y) && numel (mp_x) == numel (mp_y))
+    if (any (mp_x - mp_y))
+      error ("isShapeMultipart: NaN positions don't match");
+    else
+      mp = numel (mp_x) + 1;
+    endif
+  endif
+
+endfunction
+
+
+%!test
+%! assert (isShapeMultipart ([0 1 0], [1 0 0]), 0);
+
+%!test
+%! h = [0 0 1 NaN 2 2 NaN 3 3];
+%! k = [0 1 0 NaN 2 3 NaN 3 2];
+%! assert (isShapeMultipart (h, k), 3);
+
+%!error <x and y must be both> isShapeMultipart ([0 0 1 NaN 2 2 NaN 3 3], ...
+%!                                               [0 1 0 NaN 2 3 NaN 3 2]')
+%!error <NaN positions don't match> isShapeMultipart ([0 1 NaN 2 3 NaN 4], ...
+%!                                                    [0 1 NaN 2 NaN 3 4])
+%!error <incompatible input> isShapeMultipart ([0 0 1 NaN 2 2 NaN 3 3], ...
+%!                                       [0 1 0 NaN 2 3 NaN 3])
diff --git a/inst/km2deg.m b/inst/km2deg.m
index a80e949..80bca2b 100644
--- a/inst/km2deg.m
+++ b/inst/km2deg.m
@@ -1,5 +1,5 @@
-## Copyright (C) 2008 Alexander Barth <abarth93@users.sourceforge.net>
-## Copyright (C) 2013 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2008-2020 Alexander Barth <abarth93@users.sourceforge.net>
+## Copyright (C) 2013-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
@@ -28,7 +28,8 @@
 ## "moon", "mars", "jupiter", "saturn", "uranus", "neptune", or "pluto", in
 ## which case radius will be set to that object mean radius.
 ##
-## @seealso{deg2km}
+## @seealso{deg2km, deg2sm, km2rad, km2deg,
+## nm2deg, nm2rad, rad2km, rad2nm, rad2sm, sm2deg, sm2rad}
 ## @end deftypefn
 
 ## Author: Alexander Barth <barth.alexander@gmail.com>
diff --git a/inst/km2nm.m b/inst/km2nm.m
index 71e0dc9..82e66b9 100644
--- a/inst/km2nm.m
+++ b/inst/km2nm.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
+## Copyright (C) 2014-2020 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/km2rad.m b/inst/km2rad.m
index 4bb848b..3f81b35 100644
--- a/inst/km2rad.m
+++ b/inst/km2rad.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Pooja Rao <poojarao12@gmail.com>
+## Copyright (C) 2014-2020 Pooja Rao <poojarao12@gmail.com>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
@@ -27,7 +27,8 @@
 ## "moon", "mars", "jupiter", "saturn", "uranus", "neptune", or "pluto", in
 ## which case radius will be set to that object mean radius.
 ##
-## @seealso{km2deg}
+## @seealso{deg2km, deg2sm, km2rad, km2deg,
+## nm2deg, nm2rad, rad2km, rad2nm, rad2sm, sm2deg, sm2rad}
 ## @end deftypefn
 
 ## Author: Pooja Rao <poojarao12@gmail.com>
diff --git a/inst/km2sm.m b/inst/km2sm.m
index 3a04cc9..48bde15 100644
--- a/inst/km2sm.m
+++ b/inst/km2sm.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
+## Copyright (C) 2014-2020 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/kmlread.m b/inst/kmlread.m
new file mode 100644
index 0000000..713fbc7
--- /dev/null
+++ b/inst/kmlread.m
@@ -0,0 +1,223 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software: you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see
+## <https://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} {@var{kml} =} kmlread (@var{fname})
+## (EXPERIMENTAL) Read a Google kml file and return its contents in a struct.
+##
+## @var{name} is the name of a .kml file.
+## Currently kmlread can read Point, LineString, Polygon, Track nd Multitrack
+## entries.
+##
+## @var{kml} is a struct with fields Type, Lat, Lon, Ele, Time and Name.
+##
+## @seealso{kmzread}
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2018-05-03
+
+function outp = kmlread (fname)
+
+  fid = fopen (fname, "r");
+  if (fid > 0)
+    xml = fread (fid, Inf, "*char")';
+    fclose (fid);
+  else
+    error ("kmlread: couldn't read %s", fname);
+  endif
+
+  outp = repmat (struct ("Type", "-", ...
+                         "Lat",  [],  ...
+                         "Lon",  [],  ...
+                         "Ele",  [],  ...
+                         "Time", [],  ...
+                         "Name", "-"), 0, 1);
+
+  ## Points
+  is = 1;
+  ipt = 1;
+  while (is > 0)
+    [pnt, il, is] = getxmlnode (xml, "Point", is, 1);
+    if (is > 0)
+      outp(end+1).Type = "Point";
+      ++ipt;
+      pnam = cell2mat (regexp (xml(max (1, il - 1000):il+7), ...
+                               '<Placemark>.*?<name>(.+?)</name>.*?<Point>', "tokens")){end};
+      if (! isempty (pnam))
+        outp(end).Name = pnam;
+      else
+        outp(end).Name = ["Point #" num2str(ipt)];
+      endif
+      coords = strrep (getxmlnode (pnt, "coordinates", 1, 1), ",", " ");
+      xyz = sscanf (coords, "%f", Inf);
+      outp(end).Lon = xyz(1);
+      outp(end).Lat = xyz(2);
+      outp(end).Ele = xyz(3);
+    endif
+  endwhile
+
+  ## Linestrings / Polylines
+  is = 1;
+  iln = 1;
+  while (is > 0)
+    [lin, il, is] = getxmlnode (xml, "LineString", is, 1);
+    if (is > 0)
+      outp(end+1).Type = "Line";
+      ++iln;
+      lnam = cell2mat (regexp (xml(max (1, il - 1000):il+12), ...
+                               '<Placemark>.*?<name>(.+?)</name>.*?<LineString>', "tokens")){end};
+      if (! isempty (lnam))
+        outp(end).Name = lnam;
+      else
+        outp(end).Name = ["Line #" num2str(iln)];
+      endif
+      coords = getxmlnode (lin, "coordinates", 1, 1);
+      ## Check if we have Ele (Z). Coordinate tuples are separated by spaces
+      lines = strsplit (strtrim (coords), " ");
+      nd = numel (strfind (lines{1}, ",")) + 1;
+      xyz = reshape (sscanf (strrep (coords, ",", " "), "%f", Inf)', nd, [])';
+      outp(end).Lon = xyz(:, 1);
+      outp(end).Lat = xyz(:, 2);
+      outp(end).BoundingBox = [min(outp(end).Lon), max(outp(end).Lon); ...
+                               min(outp(end).Lat), max(outp(end).Lat)];
+      if (nd > 2)
+        outp(end).Ele = xyz(:, 3);
+        outp(end).BoundingBox = [outp(end).BoundingBox; 
+                                  min(outp(end).Ele), max(outp(end).Ele)];
+      else
+        outp(end).BoundingBox = [outp(end).BoundingBox; 
+                                 Nan, NaN];
+      endif
+    endif
+  endwhile
+  
+  ## Polygons
+  is = 1;
+  ip = 1;
+  while (is > 0)
+    [pol, il, is] = getxmlnode (xml, "Polygon", is, 1);
+    if (is > 0)
+      outp(end+1).Type = "Polygon";
+      ++ip;
+      pnam = cell2mat (regexp (xml(max (1, il - 1000):il+12), ...
+                               '<Placemark>.*?<name>(.+?)</name>.*?<Polygon>', "tokens")){end};
+      if (! isempty (pnam))
+        outp(end).Name = pnam;
+      else
+        outp(end).Name = ["Polygon #" num2str (ip)];
+      endif
+      ir = 1;
+      ## First get outer ring
+      [ring, ~, ir] = getxmlnode (pol, "outerBoundaryIs", ir);
+      coords = strrep (getxmlnode (ring, "coordinates", 1, 1), ",", " ");
+      xyz = reshape (sscanf (coords, "%f", Inf)', 3, [])';
+      ## FIXME check on CCW
+      outp(end).Lon = xyz(:, 1);
+      outp(end).Lat = xyz(:, 2);
+      outp(end).Ele = xyz(:, 3);
+      ## Next, any inner rings
+      while (ir > 0)
+        [ring, ~, ir] = getxmlnode (pol, "innerBoundaryIs", ir);
+        if (ir > 0)
+          coords = strrep (getxmlnode (ring, "coordinates", 1, 1), ",", " ");
+          xyz = reshape (sscanf (coords, "%f", Inf)', 3, [])';
+          ## FIXME check on CW
+          outp(end).Lon = [outp(end).Lon; NaN; xyz(:, 1)];
+          outp(end).Lat = [outp(end).Lat; NaN; xyz(:, 2)];
+          outp(end).Ele = [outp(end).Ele; NaN; xyz(:, 3)];
+        endif
+      endwhile
+      outp(end).BoundingBox = [min(outp(end).Lon), max(outp(end).Lon); ...
+                               min(outp(end).Lat), max(outp(end).Lat); ...
+                               min(outp(end).Ele), max(outp(end).Ele)];
+    endif
+  endwhile
+
+  ## Tracks and MultiTracks
+  ptrnT = '<when>(.*?)</when>';
+  is = em = 1;
+  it = 0;
+  while (is > 0)
+    if (em <= is)
+      ## Try to get extent of multiTrack node
+      [mtrk, ~, em] = getxmlnode (xml, "gx:MultiTrack", is, 1);
+      if (em > 0)
+        ## Get specific attributes for this Multitrack
+        mtid = getxmlattv (mtrk, "id");
+        intpm = str2double (getxmlnode (mtrk, "gx:interpolate", 10, 1));
+        ## MultiTrack; start new struct item for next tracks
+        outp(end+1).Type = "Track";
+        ++it;
+        if (isempty (mtid))
+          outp(end).Name = ["Track #" num2str(it)];
+        else
+          outp(end).Name = mtid;
+        endif
+      endif
+    endif
+
+    [trk, ~, is] = getxmlnode (xml, "gx:Track", is, 1);
+    if (is > 0)
+      if (! em)
+        ## Separate track; start new struct item
+        outp(end+1).Type = "Track";
+        ++it;
+        tnam = getxmlattv (trk, "id");
+        if (isempty (tnam))
+          outp(end).Name = ["Track #" num2str(it)];
+        else
+          outp(end) = tnam;
+        endif      
+        outp(end).BoundingBox = [min(outp(end).Lon), max(outp(end).Lon); ...
+                                 min(outp(end).Lat), max(outp(end).Lat); ...
+                                 min(outp(end).Ele), max(outp(end).Ele)];
+
+      endif
+      times = cell2mat (regexp (trk, ptrnT, "tokens"));
+      times = datenum (times, "yyyy-mm-ddTHH:MM:SSZ");
+      ptrnP = '<gx:coord>(.+?) (.+?) (.+?)</gx:coord>';
+      xyz = reshape (str2double (cell2mat (regexp (trk, ptrnP, "tokens"))), 3, [])';
+      if (isempty (outp(end).Lat))
+        outp(end).Lon = xyz(:, 1);
+        outp(end).Lat = xyz(:, 2);
+        outp(end).Ele = xyz(:, 3);
+        if (! isempty (times))
+          outp(end).Time = times;
+        endif
+      elseif (intpm)
+        outp(end).Lon = [outp(end).Lon; xyz(:, 1)];
+        outp(end).Lat = [outp(end).Lat; xyz(:, 2)];
+        outp(end).Ele = [outp(end).Ele; xyz(:, 3)];
+        if (! isempty (times))
+          outp(end).Time = [outp(end).Time; times];
+        endif
+      else
+        outp(end).Lon = [outp(end).Lon; NaN; xyz(:, 1)];
+        outp(end).Lat = [outp(end).Lat; NaN; xyz(:, 2)];
+        outp(end).Ele = [outp(end).Ele; NaN; xyz(:, 3)];
+        if (! isempty (times))
+          outp(end).Time = [outp(end).Time; NaN; times];
+        endif
+      endif
+      outp(end).BoundingBox = [min(outp(end).Lon), max(outp(end).Lon); ...
+                               min(outp(end).Lat), max(outp(end).Lat); ...
+                               min(outp(end).Ele), max(outp(end).Ele)];
+    endif
+
+  endwhile
+
+endfunction
diff --git a/inst/kmzread.m b/inst/kmzread.m
new file mode 100644
index 0000000..7dcc4ad
--- /dev/null
+++ b/inst/kmzread.m
@@ -0,0 +1,62 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software: you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see
+## <https://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} {@var{retval} =} kmzread (@var{fname}, @dots{})
+## Read a compressed Google kmz file and return its contents in a struct.
+##
+## See 'help kmlread' for more information.
+##
+## @seealso{kmlread}
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2018-05-13
+
+function out = kmzread (fzname, varargin)
+
+  ## Check filename etc.
+  [~, fn, ext] = fileparts (fzname);
+  if (isempty (ext))
+    ext = ".kmz";
+    fzname = [fzname ext];
+  elseif (! strcmp (lower (ext), ".kmz"))
+    error ("kmzread: filename extension should be '.kmz'");
+  endif
+
+  ## Unpack into temp directory
+  tmpd = tempdir;
+  fl = unzip (fzname, tempdir);
+  if (isempty (fl{1}))
+    ## Unzip failed. Check if a previous unzipped doc.kml file exists and wipe it
+    if (unlink ([tempdir filesep "doc.kml"]) == 0)
+      ## Yep existed, now try again
+      fl = unzip (fzname, tempdir);
+    else
+      error ("kmzread: couldn't unzip %s", fzname);
+    endif
+  endif
+  flname = [tempdir fl{1}];
+
+  unwind_protect
+    ## Read file
+    out = kmlread (flname, varargin{:});
+  unwind_protect_cleanup
+    ## Delete unpacked file
+    unlink (flname);
+  end_unwind_protect
+
+endfunction
diff --git a/inst/majaxis.m b/inst/majaxis.m
new file mode 100644
index 0000000..35b0423
--- /dev/null
+++ b/inst/majaxis.m
@@ -0,0 +1,80 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+## 
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+## 
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+ 
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{semimajoraxis} =} majaxis (@var{semiminoraxis}, @var{ecc}) 
+## Return the semimajor axis given the semiminoraxis (b) and eccentricity (e).
+##
+## Examples 
+##
+## Scalar input:
+## @example
+##  earth_b = 6356752.314245;  ## meter
+##  earth_ecc = 0.081819221456;
+##  a = majaxis (earth_b, earth_ecc)
+##  => a =
+##   6.3781e+06
+## @end example
+##
+## Vector input:
+## @example
+##  planets_b = [ 6356752.314245 ; 66854000 ]; ## meter
+##  planets_ecc = [ 0.081819221456 ; 0.3543164 ];
+##  planets_a = majaxis ( planets_b , planets_ecc )
+##  => planets_a =
+##      6.3781e+06
+##      7.1492e+07
+## @end example
+##  
+## @seealso{minaxis} 
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9566
+## For background see https://en.wikipedia.org/wiki/Flattening
+
+function a = majaxis (b, ecc)
+
+  if (nargin < 2)
+    print_usage ();
+  end
+
+  if (! isnumeric (b) || ! isreal (b) || ! isnumeric (ecc) || ! isreal (ecc))
+    error ( "majaxis.m : numeric input expected");
+  elseif (any (ecc < 0) || any (ecc > 1))
+    error ( "majaxis.m: eccentricity must lie in the real interval [0..1]" )
+  elseif ((length (b) != 1 && length (ecc) != 1) && ((size (b) != size (ecc))))
+    error ("vectors must be the same size")
+  else
+    a = b ./ sqrt (1 - ecc .^ 2);
+  end
+  
+endfunction
+
+%!test
+%!
+%! earth_b = 6356752.314245;  ## meter
+%! earth_ecc = 0.081819221456;
+%! assert ( majaxis (earth_b, earth_ecc), 6378137.01608, 10e-6);
+%! planets_b = [ 6356752.314245 ; 66854000 ]; ## meter
+%! planets_ecc = [ 0.081819221456 ; 0.3543164 ];
+%! assert( majaxis (planets_b, planets_ecc), [ 6378137.01608; 71492000.609327 ], 10e-6 );
+
+%!error <numeric input expected> majaxis (0.5, "ecc")
+%!error <numeric input expected> majaxis (0.5, 0.3 + 0.5i)
+%!error <numeric input expected> majaxis ("b", 0.5)
+%!error <numeric input expected> majaxis (0.3 + 0.5i , 0.5)
+%!error <eccentricity must lie> majaxis ([10; 10; 10], [0.5; 0; -0.5])
+%!error <vectors must be the same size> minaxis ( [ 6356752.314245 ; 66854000 ] , [ 0.081819221456 ; 0.3543164 ]')
\ No newline at end of file
diff --git a/inst/makesymbolspec.m b/inst/makesymbolspec.m
index 6031cb1..f523a85 100644
--- a/inst/makesymbolspec.m
+++ b/inst/makesymbolspec.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2015 Philip Nienhuis
+## Copyright (C) 2015-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
@@ -181,7 +181,7 @@ function [symspec] = makesymbolspec (geom, varargin)
       if (rem (size (varargin{ii}(3:end), 1), 2) != 0)
         error ("makesymbolspec: a property or value missing in rule #%d\n", ii);
       else
-        error ("makesymbolspec: uncomprehensible input in rul #%d\n", ii);
+        error ("makesymbolspec: uncomprehensible input in rule #%d\n", ii);
       endif
     end_try_catch
   endfor
@@ -191,8 +191,10 @@ endfunction
 
 %!test
 %% Illegal graphics properties & case of properties
-%! ssp = makesymbolspec ("Line", {"LENGTH", [100 150], "color", "b", ...
+%!warning<properties> ssp = makesymbolspec ("Line", {"LENGTH", [100 150], "color", "b", ...
 %!      "nonsense", "?", "lineWidth", 3, "markersize", "BS", "Visible", 1});
+%! ssp = makesymbolspec ("Line", {"LENGTH", [100 150], "color", "b", ...
+%!      "lineWidth", 3, "Visible", 1});
 %! assert (reshape (ssp{2}(3:end), 2, [])(1, :), {"Color", "LineWidth", ...
 %!                                                "Visible"});
 %! assert (ssp{1}, "Line");
diff --git a/inst/mapshow.m b/inst/mapshow.m
index 94369a5..013a123 100644
--- a/inst/mapshow.m
+++ b/inst/mapshow.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014,2015 Philip Nienhuis
+## Copyright (C) 2014-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/meridianarc.m b/inst/meridianarc.m
new file mode 100644
index 0000000..13b8cf7
--- /dev/null
+++ b/inst/meridianarc.m
@@ -0,0 +1,97 @@
+## Copyright (C) 2019-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSEll. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{s} =}  meridianarc (@var{phi}, @var{phi_2}, @var{spheroid}, @var{angleUnit}) 
+## Returns the meridian arch length given two latitudes @var{phi} and @var{phi_2}.
+##
+## If phi_2 is larger than phi the value will be negative.
+##
+## If no spheroid is given the default is wgs84.
+## The angleunit can be degrees or radians (the latter is default).
+##
+## Examples
+## Full options:
+## @example
+## s = meridianarc (0, 56, "int24", "degrees")
+## => s =
+## 6.2087e+06 
+## @end example
+## Short version:
+## @example
+## s = meridianarc (0, pi/4)
+## => s =
+## 4.9849e+06
+## @end example
+## If want different units:
+## @example
+## s = meridianarc (0, 56, referenceEllipsoid ("int24", "km"), "degrees")
+## => s =
+## 6208.7
+## @end example
+## @seealso{referenceEllipsoid} 
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9720
+
+function s = meridianarc (phi, phi_2, spheroid="wgs84", angleUnit="radians")
+
+  persistent intv = "-pi/2, pi/2";
+  persistent degintv = "-90, 90";
+
+  if (nargin < 2)
+    print_usage ();
+  endif
+
+  if (strncmpi (lower (angleUnit), "d", 1) == 1)
+    phi = deg2rad (phi);
+    phi_2 = deg2rad (phi_2);
+    intv = degintv;
+  endif
+  if (abs (phi) > pi / 2 || abs (phi_2) > pi / 2)
+    error ("meridianarc: latitudes must lie in interval [%s]", intv);
+  endif
+
+  if isempty (spheroid)
+    spheroid = "wgs84";
+  end
+
+  ## From: Algorithms for global positioning. Kai Borre and Gilbert Strang pg 373
+  ## Note: Using integral instead of Taylor Expansion 
+  if (isstruct (spheroid))
+    E = spheroid;
+  elseif (ischar (spheroid))
+    E = referenceEllipsoid (spheroid);
+  else
+    error ("meridianarc.m: spheroid must be a string or a stucture");
+  endif
+
+  e_sq = E.Eccentricity ^ 2;
+  F = @(x) ((1 - e_sq * sin(x) ^ 2) ^ (-3 / 2));
+  s = E.SemimajorAxis * (1 - e_sq) * quad ( F, phi, phi_2, 1.0e-12);
+
+endfunction
+
+%!test
+%! s = meridianarc (0, 56, "int24", "degrees");
+%! assert (s, 6208700.08662672, 10e-6)
+
+%!error <spheroid> meridianarc ( 0, pi/4, 7)
+%!error <spheroid> meridianarc ( 0, pi/4, 7i)
+%!error <latitudes> meridianarc (-2, 2)
+%!error <latitudes> meridianarc (-91, 91, "", "d")
+
diff --git a/inst/minaxis.m b/inst/minaxis.m
new file mode 100644
index 0000000..bdc61fa
--- /dev/null
+++ b/inst/minaxis.m
@@ -0,0 +1,80 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+## 
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+## 
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+ 
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{semiminoraxis} =} minaxis (@var{semimajoraxis}, @var{ecc}) 
+## Return the semiminor axis given the semimmajor axis (a) and eccentricity (ecc).
+## 
+## Examples 
+##
+## Scalar input:
+## @example
+##  earth_a = 6378137; %m
+##  earth_ecc = 0.081819221456;
+##  earth_b = minaxis (earth_a, earth_ecc)
+##  => earth_b = 
+##      6.3568e+06
+## @end example
+##
+## Vector input:
+## @example
+##  planets_a = [ 6378137 ; 66854000 ];
+##  planets_ecc = [ 0.081819221456 ; 0.3543164 ];
+##  planets_b = minaxis (planets_a , planets_ecc)
+##  => planets_b =
+##      6.3568e+06
+##      6.2517e+07
+## @end example
+## 
+## @seealso{majaxis} 
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9566
+## For background see https://en.wikipedia.org/wiki/Flattening
+
+function b = minaxis (a, ecc)
+  
+  if (nargin < 2)
+    print_usage ();
+  end
+
+  if (! isnumeric (a) || ! isreal (a) || ! isnumeric (ecc) || ! isreal (ecc))
+    error ("minaxis.m : numeric input expected");
+  elseif (any (ecc < 0) || any (ecc > 1))
+    error ("minaxis.m: eccentricity must lie in interval [0..1]")
+  elseif ((length (a) != 1 && length(ecc) != 1) && ((size (a) != size (ecc))))
+    error ("vectors must be the same size")
+  else
+    b = a .* sqrt ( 1 - ecc .^ 2 );
+  end
+  
+endfunction
+
+%!test
+%!
+%! earth_a = 6378137;
+%! earth_ecc = 0.081819221456;
+%! assert ( minaxis (earth_a, earth_ecc), 6356752.2982157, 10e-8 )
+%! planets_a = [ 6378137 ; 66854000 ];
+%! planets_ecc = [ 0.081819221456 ; 0.3543164 ];
+%! assert ( minaxis (planets_a, planets_ecc), [ 6356752.29821572 ; 62516886.8951319 ], 10e-8 )
+
+%!error <numeric input expected> minaxis (0.5, "ecc")
+%!error <numeric input expected> minaxis (0.5, 0.3 + 0.5i)
+%!error <numeric input expected> minaxis ("a", 0.5)
+%!error <numeric input expected> minaxis (0.3 + 0.5i , 0.5)
+%!error <vectors must be the same size> minaxis ( [ 6378137 ; 66854000 ], [ 0.081819221456 ; 0.3543164 ]')
+%!error <eccentricity must lie> minaxis ([10; 10; 10], [0.5; 0; -0.5])
diff --git a/inst/n2ecc.m b/inst/n2ecc.m
new file mode 100644
index 0000000..1bddfe7
--- /dev/null
+++ b/inst/n2ecc.m
@@ -0,0 +1,74 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{ecc} =} n2ecc (@var{n})
+## This returns the eccentricity given the third flattening (n).
+##
+## Examples:
+##
+## Scalar input:
+## @example
+##  n_earth = 0.0016792;
+##  ecc_earth = n2ecc (n_earth)
+##  => ecc_earth = 0.081819
+## @end example 
+##
+## Vector input:
+## @example
+##  n_vec = [ 0.0016792 0.033525 ];
+##  ecc = n2ecc (n_vec)
+##  => ecc =
+##	 0.081819     0.35432
+## @end example
+##
+## @seealso{n2ecc}
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9566
+## For background see https://en.wikipedia.org/wiki/Flattening
+
+function ecc = n2ecc (n)
+
+  if (nargin < 1)
+    print_usage ();
+  end
+  if (! isnumeric (n) || ! isreal (n) )
+    error ("n2ecc.m: numeric input expected");
+  elseif (any (n < 0) || any (n > 1))
+    error ("n2ecc.m: n should lie in the real interval [0..1]" )
+  else
+    ecc = sqrt (4 * n ./ (1 + n) .^2);
+  end
+  
+endfunction
+
+%!test
+%!
+%! n_earth = 0.001679221647179929;
+%! n_jupiter = 0.03352464537391420;
+%! n_vec = [ n_earth  n_jupiter ];
+%! assert (n2ecc (n_earth) , .081819221456 , 10e-12); 
+%! assert (n2ecc (n_vec), [0.08181922 0.3543164], 10e-8)
+
+%!error <numeric input expected> n2ecc ("n")
+%!error <numeric input expected> n2ecc (0.5 + 3i)
+%!error <n should lie> n2ecc (-1)
+%!error <n should lie> n2ecc (2)
+%!error <n should lie> n2ecc (-Inf)
+%!error <n should lie> n2ecc (Inf)
+
diff --git a/inst/nm2deg.m b/inst/nm2deg.m
index b9818a8..332d912 100644
--- a/inst/nm2deg.m
+++ b/inst/nm2deg.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Pooja Rao <poojarao12@gmail.com>
+## Copyright (C) 2014-2020 Pooja Rao <poojarao12@gmail.com>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
diff --git a/inst/nm2km.m b/inst/nm2km.m
index b783396..596ccb2 100644
--- a/inst/nm2km.m
+++ b/inst/nm2km.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
+## Copyright (C) 2014-2020 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/nm2rad.m b/inst/nm2rad.m
index bda4fd7..f043706 100644
--- a/inst/nm2rad.m
+++ b/inst/nm2rad.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Pooja Rao <poojarao12@gmail.com>
+## Copyright (C) 2014-2020 Pooja Rao <poojarao12@gmail.com>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
diff --git a/inst/nm2sm.m b/inst/nm2sm.m
index f1f9514..91ac8de 100644
--- a/inst/nm2sm.m
+++ b/inst/nm2sm.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
+## Copyright (C) 2014-2020 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/parametricLatitude.m b/inst/parametricLatitude.m
new file mode 100644
index 0000000..0ac0c2e
--- /dev/null
+++ b/inst/parametricLatitude.m
@@ -0,0 +1,93 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+## 
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+## 
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{beta} =} parametricLatitude (@var{phi}, @var{flattening}) 
+## @deftypefnx {Function File} {@var{beta} =} parametricLatitude (@var{phi}, @var{flattening}, @var{angleUnit}) 
+## Returns parametric latitude given geodetic latitude (phi) and flattening.
+##
+## The parametric latitude @var{beta} is also known as a reduced latitude.
+## The default input and output is in degrees; use optional third parameter
+## @var{angleUnit} for radians.  @var{phi} can be a scalar, vector, matrix
+## or any ND array.  @var{flattening} must be a scalar value in the interval
+## [0..1).
+##
+## Examples:
+## Scalar input:
+## @example
+## beta = parametricLatitude (45, 0.0033528)
+## => beta =
+##  44.904
+## @end example
+##
+## Also can use radians:
+## @example
+## beta = parametricLatitude (pi/4, 0.0033528, "radians")
+## => beta =
+##  0.78372
+## @end example
+##
+## Vector Input:
+## @example
+## phi = 35:5:45;
+## beta = parametricLatitude (phi, 0.0033528)
+## => beta =
+##  34.91      39.905      44.904
+## @end example
+## @seealso{geocentricLatitude , geodeticLatitudeFromGeocentric , geodeticLatitudeFromParametric} 
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9640
+
+function beta = parametricLatitude (phi, flattening, angleUnit="degrees")
+  
+  if (nargin < 2)
+    print_usage ();
+  endif
+ 
+  if (! isnumeric (phi) || ! isreal (phi) || ...
+      ! isnumeric (flattening) || ! isreal (flattening))
+    error ("parametricLatitude : numeric input expected");
+  elseif (! isscalar (flattening))
+    error ("parametricLatitude: scalar value expected for flattening");
+  elseif (flattening < 0 || flattening >= 1)
+    error ("parametricLatitude: flattening must lie in the real interval [0..1)" );
+  elseif (! ischar (angleUnit) ||! ismember (lower (angleUnit(1)), {"d", "r"}))
+    error ("parametricLatitude: angleUnit should be one of 'degrees' or 'radians'");
+  endif
+
+  if (strncmpi (angleUnit, "r", 1) == 1)
+    ## From: Algorithms for global positioning. Kai Borre and Gilbert Strang pg 371 
+    beta = atan ((1 - flattening) * tan (phi));
+  else
+    beta = atand ((1 - flattening) * tand (phi));
+  end
+  
+
+endfunction
+
+%!test
+%! earth_flattening = 0.0033528 ;
+%! assert (parametricLatitude (45, earth_flattening), 44.903787, 10e-6)
+%! assert (parametricLatitude (pi/4, earth_flattening, 'radians'), 0.78372, 10e-6)
+
+%!error <numeric input expected> parametricLatitude (0.5, "flat")
+%!error <numeric input expected> parametricLatitude (0.5, 5i)
+%!error <numeric input expected> parametricLatitude ("phi", 0.0033528)
+%!error <numeric input expected> parametricLatitude (5i, 0.0033528 )
+%!error <scalar value expected> parametricLatitude ([45 50], [0.7 0.8])
+%!error <flattening must lie> parametricLatitude (45, 1)
+%!error <angleUnit> parametricLatitude (45, 0.0033528, "km")
diff --git a/inst/polycut.m b/inst/polycut.m
new file mode 100644
index 0000000..4423a93
--- /dev/null
+++ b/inst/polycut.m
@@ -0,0 +1,54 @@
+## Copyright (C) 2017-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {Function File} [@var{Xo}, @var{Yo}] = polycut (@var{Xi}, @var{Yi})
+## @deftypefnx {Function File} [@var{Xo}, @var{Yo}, @var{Zo}] = polycut (@var{Xi}, @var{Yi}, @var{Zi})
+## @deftypefnx {Function File} [@var{XY_o}] = polycut (@var{XY_i})
+## Reorder nested multipart polygons in such a way that branch cuts aren't
+## drawn when using the patch command.
+##
+## Normally when drawing multipart nested polygons (with holes and other
+## polygons inside the holes; polygon parts separated by NaNs) holes will be
+## filled.  Connecting the polygon parts by deleting the NaNs leads to edges
+## of some polygon parts to be drawn across neighboring polygon parts.
+## polycut reorders the polygon parts such that the last vertices of polygon
+## parts have minimum distance to the first vertices of the next parts,
+## avoiding the connecting lines ("branch cuts") to show up in the drawing.
+##
+## Input consists of separate X, Y, and -optionally- Z vectors, or an Nx2 or
+## Nx3 matrix of vertex coordinates (X, Y) or (X, Y, Z).  If individual X and
+## Y vectors were input, the output consists of the same number of vectors.
+## If an Nx 2 or Nx3 array was input, the output will be an Nx2 or Nx3 matrix
+## as well.
+##
+## polycut is a mere wrapper around the function polygon2patch in the OF
+## geometry package.
+##
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2017-11-10
+
+function [X, Y, Z] = polycut (varargin)
+
+  if (isempty (which ("polygon2patch")))
+    error ("function polygon2patch not found. OF geometry package \
+installed and loaded?");
+  endif
+  [X, Y, Z] = polygon2patch (varargin{:});
+
+endfunction
diff --git a/inst/private/__dbl2int64__.m b/inst/private/__dbl2int64__.m
new file mode 100644
index 0000000..0fa8478
--- /dev/null
+++ b/inst/private/__dbl2int64__.m
@@ -0,0 +1,47 @@
+## Copyright (C) 2017-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+function [opol, xy_mean, xy_magn] = __dbl2int64__ (inpoly, clippoly=[], xy_mean=[], xy_magn=[])
+
+  if (isempty (clippoly))
+    clippoly = zeros (0, size (inpoly, 2));
+  endif
+  if (isempty (xy_mean))
+    ## Convert & scale to int64 (that's what Clipper works with)
+    ## Find (X, Y) translation
+    xy_mean = mean ([inpoly; clippoly] (isfinite ([inpoly; clippoly](:, 1)), :));
+    ## Find (X, Y) magnitude
+    xy_magn = max ([inpoly; clippoly] (isfinite ([inpoly; clippoly](:, 1)), :)) ...
+            - min ([inpoly; clippoly] (isfinite ([inpoly; clippoly](:, 1)), :));
+    ## Apply (X,Y) multiplication (floor (log10 (intmax ("int64"))) = 18)
+    xy_magn = 10^(17 - ceil (max (log10 (xy_magn))));
+  endif
+
+  ## Scale inpoly coordinates to optimally use int64
+  inpoly(:, 1:2) -= xy_mean;
+  inpoly         *= xy_magn;
+
+  idin = [ 0 find(isnan (inpoly (:, 1)))' numel(inpoly (:, 1))+1 ];
+  ## Provisional preallocation. npolx is average nr. of vertices per polygon
+  npolx = fix (size (inpoly, 1) / numel (idin)-1);
+  npoly = size (inpoly, 2);
+  opol = repmat (struct ("x", zeros (npolx, npoly), "y", zeros (npolx, npoly)), ...
+                         1, numel(idin) - 1);
+  for ii=1:numel (idin) - 1
+    opol(ii).x = int64 (inpoly(idin(ii)+1:idin(ii+1)-1, 1));
+    opol(ii).y = int64 (inpoly(idin(ii)+1:idin(ii+1)-1, 2));
+  endfor
+
+endfunction
diff --git a/inst/private/clipplg.m b/inst/private/clipplg.m
deleted file mode 100644
index 7c523aa..0000000
--- a/inst/private/clipplg.m
+++ /dev/null
@@ -1,207 +0,0 @@
-## Copyright (C) 2014 Philip Nienhuis
-## 
-## This program is free software; you can redistribute it and/or modify it
-## under the terms of the GNU General Public License as published by
-## the Free Software Foundation; either version 3 of the License, or
-## (at your option) any later version.
-## 
-## This program is distributed in the hope that it will be useful,
-## but WITHOUT ANY WARRANTY; without even the implied warranty of
-## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-## GNU General Public License for more details.
-## 
-## You should have received a copy of the GNU General Public License
-## along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-## -*- texinfo -*- 
-## @deftypefn {Function File} [@var{val}, @var{npts}, @var{pptr}] = clipplg (@var{val}, @var{npts}, @var{pptr}, @var{sbox}[, @var{styp]})
-## Undocumented internal function for clipping polygons & interpolating Z & M
-## values.
-##
-## @seealso{}
-## @end deftypefn
-
-## Author: Philip Nienhuis <prnienhuis@users.sf.net>
-## Created: 2014-11-18
-## Updates:
-## 2014-11-22 Create stanza for finding back vertices and interpolating Z & M
-## 2014-11-25 Fix interpolating M & Z values, properly treat new corner points
-##            of clipped polygons
-## 2014-11-26 Update tnpt and tnpr arrays
-## 2015-07-10 Provision for segments crossed twice by clipping polygon
-
-function [val, tnpt, tnpr] = clipplg (val, tnpt, tnpr, sbox, styp=5)
-
-  ## Indices to start of each subfeature, plus end+1
-  tnprt = [(tnpr + 1) tnpt+1];
-
-  ## Initialize total number of clipped vertices
-  tnptclp = 0;
-  tnprclp = cell (numel (tnpr, 1));
-
-  for kk=1:numel (tnpr)
-    ## Work from end back to start of subfeatures to avoid mixing up index arrays
-    jj = numel (tnpr) - kk + 1;
-    ## Select rows belonging to this partial feature. First save non-selected rows
-    b_val = e_val = [];
-    if (jj > 1)
-      ## There's one or more subfeatures lower down
-      b_val = val(1:tnprt(jj)-1, :);
-    endif
-    if (jj < numel (tnpr))
-      ## There's one or more subfeatures higher up
-      e_val = val(tnprt(jj+1):end, :);
-    endif
-    tval = val(tnprt(jj):tnprt(jj+1)-1, :);
-    ## oc_polybool is in OF geometry package
-    [X, Y, npol, b, c] = oc_polybool (tval(:, 1:2), sbox, 'AND');
-
-    ## Initialize new number of points & new part pointers in clipped polygon(s)
-    nptclp = 0;
-    nprclp = 0;
-    valn = [];
-    if (npol)
-      ## Make an XY matrix, remove NaNs on upper and lower row
-      valc = [X Y](2:end-1, :);
-      ## Augment NaNs for Z and M, and augment type + shape record index columns
-      ncl = size (valc, 1);
-      valc = [ valc NaN(ncl, 2) tval(1, 5)*ones(ncl, 1) tval(1, 6)*ones(ncl, 1) ];
-      ## Pointers to subpolygons resulting from clipping
-      ipt = find (isnan (valc(:, 1)))';
-      ipt = [ 0 ipt (size (valc, 1) + 1) ];
-      ## For each new polygon...
-      for ipol=1:npol
-        valn = valc(ipt(ipol)+1:ipt(ipol+1)-1, :);
-        ## Update total number of points in clipped polygon(s)
-        nptclp += size (valn, 1);
-        tnptclp += size (valn, 1);
-        ## Add a new 0-based pointer to next part
-        nprclp = [ nprclp nptclp ];
-        ## Compute all interdistances. distancePoints is in OF geometry package
-        ## Avoid polygon end point ( = start point)
-        dsts = distancePoints (valn(1:end-1, 1:2), tval(1:end-1, 1:2));
-        ## Find matching points in sub and out polygon (row, col)
-        [rw, cl] = ind2sub (size (dsts), find (abs (dsts) < eps));
-        ## Transfer known Z and M-values
-        valn(rw, 3:4) = tval(cl, 3:4);
-        ## cl indices refer to original shape, rw indices to clipped shape
-        if (numel (cl) >= 1)
-          ## Separate polygon segments clipped, or vertex on bounding box side
-          ## For each valn row coords not in tval, interpolate Z and M values
-          im = setdiff ([1:size(valn, 1)-1], rw);
-          ## mi equals cl filled with zeros for non-matches, to easen indexing
-          mi = zeros (1, size (valn, 1) - 1);
-          mi(rw) = cl; 
-          ## Find direction of polyline
-          pdir = find (abs (diff (rw)) - 1 < eps);
-          if (isempty (pdir))
-            ## Single point within bounding box. Direction doesn't matter then
-            drctn = 1;
-          else
-            drctn = sign (diff (rw([pdir pdir+1])))(1);
-          endif
-          for ii=1:numel (im)
-            ## Get matching outer vertex. Below IF-ELSEIF order = critical to
-            ## avoid index out-of-range errors
-            if (im(ii) == 1)
-              ## Clipped off outer vertex = previous in tval. diff(cl) = direction
-              intpl = true;
-              idx = mi(im(ii)+1) - drctn;
-              ovtx = tval(idx, :);
-              cvtx = tval(mi(im(ii)+1), :);
-            elseif ((! ismember (im(ii)-1, rw)) && (! ismember (im(ii)+1, rw)))
-              ## Probably a corner point. Just retain NaN values
-              intpl = false;
-            elseif (! ismember (im(ii)-1, rw))
-              ## Clipped off outer vertex = previous in tval. diff(cl) = direction
-              intpl = true;
-              idx = mi(im(ii)+1) - drctn;
-              ovtx = tval(idx, :);
-              cvtx = tval(mi(im(ii)+1), :);
-            elseif (! ismember (im(ii)+1, rw))
-              ## Clipped off outer vertex = next in tval. diff(cl) = direction
-              intpl = true;
-              idx = mi(im(ii)-1) + drctn;
-              ovtx = tval(idx, :);
-              cvtx = tval(mi(im(ii)-1), :);
-            endif
-            ## Parent points found, now interpolate M and Z (if appropriate)
-            if (intpl && styp > 5)
-              ## Compute missing M and Z values. Invoke largest diff of X/Y coordinates
-              difx = abs (cvtx(1) - ovtx(1));
-              dify = abs (cvtx(2) - ovtx(2));
-              if (difx > dify)
-                ## X distance is greater
-                fac = (valn(im(ii), 1) - cvtx(1)) / difx;
-              else
-                ## Y distance is greater
-                fac = (valn(im(ii), 2) - cvtx(2)) / dify;
-              endif
-              fac = abs(fac);
-              ## FIXME a debug stmt to detect wrong interpolation => wrong vertices
-              if (fac > 1.0)
-                printf ("Oops - fac > 1..\n");
-           %     keyboard
-              endif
-              if (isfinite (ovtx(3)))
-                valn(im(ii), 3) = fac * (ovtx(3) - cvtx(3)) + cvtx(3); ## Z-value
-              endif
-              if (isfinite (ovtx(4)))
-                valn(im(ii), 4) = fac * (ovtx(4) - cvtx(4)) + cvtx(4); ## M-value
-              endif
-            endif
-          endfor
-          ## Remove last nprclp entry and temporarily store it in a cell arr
-          tnprclp(jj) = nprclp;
-
-        elseif (numel (cl) == 0)
-          ## One polygon segment clipped twice. Simply assign nearest Z & M values
-          ## FIXME proper interpolation required
-          ## Find points interpolated on segment(s); they're not in sbox
-          [im, ix] = min (distancePoints (sbox(1:end-1, :), valn(1:end-1, 1:2)));
-          im = find (im > 0);
-          ix = ix(im);
-          ## Find nearest polygon points (could be on another polygon segment !)
-          [~, ix] = min (distancePoints (tval(1:end-1, 1:2), valn(im, 1:2)));
-          ## Assign Z and M values
-          valn(im, 3:4) = tval(ix, 3:4);
-          ## Remove last nprclp entry and temporarily store it in a cell arr
-          tnprclp(jj) = nprclp;
-
-        endif
-        ## Last row of polygon equals first
-        valn(end, :) = valn(1, :);
-        ## Augment new polygon after (yet untouched) previous polygons
-        b_val = [ b_val; valn ];
-
-      endfor                                                ## clipped subpolygons
-
-    else
-      ## No intersection at all. Just drop tval
-      % tnprclp = {};
-    endif
-
-    val = [b_val ; e_val];
-    tnprt(jj+1:end) -= tnprt(jj+1) - tnprt(jj) - size (valn, 1);
-    if (isempty (valn))
-      ## This subfeature has no points in boundingbox +> drop from list
-      tnprt(jj+1) = [];
-    endif
-
-  endfor
-
-  ## Adapt & clean up npt
-  tnpt = tnptclp;
-  ## Adapt & clean up npr. Concatenate all pointers created by oc_polybool
-  tnpr = [ tnprclp{1} ];
-  for ii=2:numel (tnprclp)
-    ## Skip empty entries
-    if (! isempty (tnprclp{ii}))
-      tnpr = [tnpr(1:end-1) (tnprclp{ii} + tnpr(end)) ];
-    endif
-  endfor
-  if (! isempty (tnpr))
-    tnpr(end) = [];
-  endif
-
-endfunction
diff --git a/inst/private/clippln.m b/inst/private/clippln.m
index 7d8a575..cfcf32c 100644
--- a/inst/private/clippln.m
+++ b/inst/private/clippln.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Philip Nienhuis
+## Copyright (C) 2014-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
@@ -16,7 +16,7 @@
 ## -*- texinfo -*- 
 ## @deftypefn {Function File} [@var{val}, @var{npts}, @var{pprt}] = clipplg (@var{val}, @var{npts}, @var{pprt}, @var{sbox}, @var{styp})
 ## Undocumented internal function for clipping (poly)lines within a bounding
-## box and interpolating M and Z-values.
+## box and copying M and Z-values from nearest old vertex.
 ##
 ## @seealso{}
 ## @end deftypefn
@@ -24,162 +24,28 @@
 ## Author: Philip Nienhuis <prnienhuis@users.sf.net>
 ## Created: 2014-12-01
 
-function [val, tnpt, tnpr] = clippln (val, tnpt, tnpr, sbox, styp=3)
+function [valn, tnpt, tnpr] = clippln (val, tnpt, tnpr, sbox, styp=3)
 
-  ## Backup
-  btnpr = tnpr;
-  ## Prepare augmented npr array for easier indexing into subfeatures
-  ttnpr = [tnpr tnpt];
-  ctnpr = {};
-  ## Initialize output array
-  valt = [];
-
-  ## First step is to check all polyline vertices whether they lie in sbox
-  [aa, bb] = inpolygon (val(:, 1), val(:, 2), sbox(:, 1), sbox(:, 2));
-  if (any (aa) || any (bb))
-    ## So there are. Morph bounding box into something that OF geometry likes:
-    ## Parametric representation of bounding box. "createLine" is in OF geometry
-    ssbox = createLine (sbox(1:4, :), sbox (2:5, :)); 
-## Create sbx from sbox ([minx max miny maxy])
-sbx = [min(sbox(:, 1)), max(sbox(:, 1)), min(sbox(:, 2)), max(sbox(:, 2))];
-    ## For those points ON the boundary no interpolation is needed.
-    ## First treat those points requiring interpolation (1st inside,
-    ## 2nd outside or vice versa)
-    for ll=1:numel (tnpr)
-      ## Start at end of polyline-part to avoid mixing up tnpr pointers
-      ii = numel (tnpr) - ll + 1;
-      nprt = [];
-      ## Select polyline part
-      valn = val(ttnpr(ii)+1:ttnpr(ii+1), :);
-      a = aa(ttnpr(ii)+1:ttnpr(ii+1));
-      if (any (a))
-        b = bb(ttnpr(ii)+1:ttnpr(ii+1));
-        da = diff (a);
-        idx = find (da);
-        ## Find out which bounding box segments have been crossed where
-        ## 1. Parametric representation of line
-        lines = createLine (valn(idx, 1:2), valn(idx+1, 1:2));
-        ## 2. Compute intersections. clipLine & distancePoints are in OF geometry
-        for jj=1:numel (idx)
-          ## Start at end of polyline-part to avoid mixing up tnpr pointers
-          kk = numel (idx) - jj + 1;
-          ## Skip points on border
-          if (! b(idx(kk)+1))
-            intsc = reshape (clipLine (lines(kk, :), sbx), 2, 2)';
-            dst = distancePoints (intsc, valn(idx(kk):idx(kk)+1, 1:2));
-            ## If segment goes out, take nearest point to valn(idx(kk)+1)
-            if (da(idx(kk)) < 1)
-              [~, ix] = min (dst(:, 2));
-            else
-              [~, ix] = min (dst(:, 1));
-            endif
-            fac = dst(ix, 2) / sum (dst(2, :));
-            intsc = intsc (ix, :);
-            ## Insert new intersection point
-            valn(idx(kk)+2:end+1, :) = valn(idx(kk)+1:end, :);
-            valn(idx(kk)+1, 1:2) = intsc(1:2);
-            if (styp > 3)
-              valn(idx(kk)+1, 3:4) = valn(idx(kk)+2, 3:4) + fac * ...
-                                     (valn(idx(kk), 3:4) - valn(idx(kk)+2, 3:4));
-            else
-              valn(idx(kk)+1, 3:4) = [NaN NaN];
-            endif
-            ## Also update a, b, da and idx. Also mark first point outside sbox
-            aa(ttnpr(ii)+idx(kk):ttnpr(ii)+idx(kk)+1) = 1;
-            a = [ a(1:idx(kk)); 1; a(idx(kk)+1:end) ];
-            b = [ b(1:idx(kk)); 1; b(idx(kk)+1:end) ];
-          endif
-          if (da(idx(kk)) < 0)
-            ## Segment leaves bbox. Replace first outer point with NaN row
-            valn(idx(kk)+2, :) = NaN (1, 6);
-            ## Be sure to include NaN row
-            a(idx(kk)+2) = 1;
-          endif
-        endfor
-        ## Update valt, ttnpr
-        valn = valn(find(a), :);
-        if (! isempty (valn))
-          ## Remove last NaN row if present
-          if (all (isnan (valn(end, 1:2))))
-            valn(end,:) = [];
-          endif
-          isn = 1;
-          while (! isempty (isn))
-            isn = find (isnan (valn(:, 1)));
-            if (! isempty (isn))
-              ## Insert new subfeature pointer. npart pointers are 0-based
-              nprt = [ nprt isn(1) ];
-              valn(isn(1), :) = [];
-            endif
-          endwhile
-          ## Build up new points from top down
-          valt = [ valn; valt ];
-          ## nprt only gets non-empty if a polyline part was split up
-          ## FIXME moet net als bij polygons
-          ttnpr = [ ttnpr(1:ii) (nprt+ttnpr(ii)-1) ttnpr(ii+1:end) ];
-        endif
-      endif
-    endfor
-    tnpt = size (valt, 1);
-    tnpr = ttnpr(1:end-1);
+  ## Clip (intersection)
+  if (mod (styp, 10) == 3)
+    [valn, nparts] = clipPolyline_clipper (val(:, 1:2), sbox, 1);
+  else
+    [valn, nparts] = clipPolygon_clipper (val(:, 1:2), sbox, 1);
   endif
 
-  ## There's still the possibility of segments crossing through Bounding Box
-  ## w/o having points inside. Search these segments one by one
-  cc = find (! aa);
-  if (numel (cc) > 1)
-    ## Find discontinuities; and merge wit tnpr (multipart) discontinuities
-    ci = find (diff(cc) > 1)';
-    ## Make sure to only include multipart discontinuities within range of cc
-    ctnpr = unique ([max(btnpr, cc(1)-1) cc(ci)' min(cc(end), size (val, 1))]);
-    ## Create sbx from sbox ([minx max miny maxy])
-    sbx = [min(sbox(:, 1)), max(sbox(:, 1)), min(sbox(:, 2)), max(sbox(:, 2))];
-    for ic=1:numel (ctnpr) - 1
-      valc = val(ctnpr(ic)+1:ctnpr(ic+1), :);
-      ## Eliminate segments that lie to one outside of the bounding box.
-      ## Step 1: assess which side of the bounding box the segments lie
-      f1 = valc(:, 1) < min (sbox(:, 1));
-      f2 = valc(:, 1) > max (sbox(:, 1));
-      f3 = valc(:, 2) < min (sbox(:, 2));
-      f4 = valc(:, 2) > max (sbox(:, 2));
-      ff = [f1'; f2' ; f3' ; f4']';
-      ## Step 2: find those segments that cross > 2 extended sbox boundary line
-      dd = find (sum ([abs(diff(f1)'); abs(diff(f2)'); ...
-                       abs(diff(f3)'); abs(diff(f4)')]) > 1);
-      ## If there are any vertices changing orientation w.r.t. bounding box:
-      if (! isempty (dd))
-        ## Create array of lines potentially crossing sbox
-        lines = [];
-        for ii=1:numel (dd)
-          lines = [ lines; createLine(valc(dd(ii), 1:2), valc(dd(ii)+1, 1:2))];
-        endfor
-        ## For each of that segment, try to compute intersections with sbox
-        for ii=1:numel (dd)
-          ## clipLine is in OF geometry
-          jntsc = reshape (clipLine (lines, sbx), 2, 2)';
-          ## Check if there are any intersections at all
-          if (! any (isnan (jntsc)))
-            valn = [ jntsc NaN(2, 4) ];
-            ## Interpolate M and Z values. valc(dd(ii)+1) also required ...
-            dist = distancePoints (valc(dd(ii):dd(ii)+1, 1:2), valn(:, 1:2));
-            ## ... for length of original segment:
-            sl = sum (dist(:, 1));
-            ## Find closest point of original segment
-            valn(1, 3:4) = valc(dd(ii), 3:4) + dist(1, 1) / sl * ...
-                           (valc(dd(ii)+1, 3:4) - valc(dd(ii), 3:4));
-            valn(2, 3:4) = valc(dd(ii), 3:4) + dist(1, 2) / sl * ...
-                           (valc(dd(ii)+1, 3:4) - valc(dd(ii), 3:4));
-            ## Adapt tnpr
-            tnpr = [ tnpr size(valt, 1) ];
-            valt = [ valt; valn ];
-          endif
-        endfor
-        tnpr = unique (tnpr);
-      endif
-    endfor
-  endif
-  
-  valt(:, 5:6) = repmat (val(1, 5:6), size (valt, 1), 1);
-  val = valt;
+  ## Set up pointers to subpolygons
+  idn = [0 find(isnan (valn(:, 1)))' size(valn, 1)+1];
+  tnpr = idn(1:end-1);
+  ## Setup Z/M/nr/type columns
+  for ii=1:nparts
+    dists = distancePoints (val(:, 1:2), valn(idn(ii)+1:idn(ii+1)-1, 1:2));
+    [mind, idm] = min (dists);
+    ## Simply copy over Z & M values & no. and type of nearest "old" vertex
+    valn(idn(ii)+1:idn(ii+1)-1, 3:6) = val(idm, 3:6);
+  endfor
+  ## Fix up pointers and vertices
+  valn(idn(2:end-1), :) = [];
+  tnpr = tnpr - [0 : numel(tnpr)-1];
+  tnpt = size (valn, 1);
 
 endfunction
diff --git a/inst/private/spheres_radius.m b/inst/private/spheres_radius.m
index 2e22da0..10f1778 100644
--- a/inst/private/spheres_radius.m
+++ b/inst/private/spheres_radius.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2013 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2013-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/inst/rad2km.m b/inst/rad2km.m
index 731b8c4..3225f3d 100644
--- a/inst/rad2km.m
+++ b/inst/rad2km.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Pooja Rao <poojarao12@gmail.com>
+## Copyright (C) 2014-2020 Pooja Rao <poojarao12@gmail.com>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
@@ -27,7 +27,8 @@
 ## "moon", "mars", "jupiter", "saturn", "uranus", "neptune", or "pluto", in
 ## which case radius will be set to that object mean radius.
 ##
-## @seealso{km2rad}
+## @seealso{deg2km, deg2sm, km2rad, km2deg,
+## nm2deg, nm2rad, rad2km, rad2nm, rad2sm, sm2deg, sm2rad}
 ## @end deftypefn
 
 ## Author: Pooja Rao <poojarao12@gmail.com>
diff --git a/inst/rad2nm.m b/inst/rad2nm.m
new file mode 100644
index 0000000..06e4a88
--- /dev/null
+++ b/inst/rad2nm.m
@@ -0,0 +1,62 @@
+## Copyright (C) 2014-2020 Pooja Rao
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+##
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+##
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{nm} =} rad2nm (@var{rad})
+## @deftypefnx {Function File} {@var{nm} =} rad2nm (@var{rad}, @var{radius})
+## @deftypefnx {Function File} {@var{nm} =} rad2nm (@var{rad}, @var{sphere})
+## Converts angle in radians to distance in nautical miles by multiplying angle
+## with radius.
+##
+## Calculates the distances @var{nm} in a sphere with @var{radius} (also in
+## nautical miles) for the angles @var{rad}.  If unspecified, radius defaults to
+## 3440 nm, the mean radius of Earth.
+##
+## Alternatively, @var{sphere} can be one of "sun", "mercury", "venus", "earth",
+## "moon", "mars", "jupiter", "saturn", "uranus", "neptune", or "pluto", in
+## which case radius will be set to that object's mean radius.
+##
+## @seealso{deg2km, deg2nm, deg2sm, km2rad, km2deg,
+## nm2deg, nm2rad, rad2km, rad2sm, sm2deg, sm2rad}
+## @end deftypefn
+
+## Built with insight from
+## Author: Pooja Rao <poojarao12@gmail.com>
+## Adapted from deg2km.m by Anonymous contributor, see patch #9709
+
+function nm = rad2nm (rad, radius = "earth")
+
+  ## Check arguments
+  if (nargin < 1 || nargin > 2)
+    print_usage();
+  elseif (ischar (radius))
+    ## Get radius of sphere with its default units (km)
+    radius = km2nm (spheres_radius (radius));
+  ## Check input
+  elseif (! isnumeric (radius) || ! isreal (radius))
+    error ("rad2nm: RADIUS must be a numeric scalar");
+  endif
+  nm = (rad * radius);
+
+endfunction
+
+
+%!test
+%!assert (nm2rad (rad2nm (10)), 10, 10*eps);
+%!assert (nm2rad (rad2nm (10, 80), 80), 10, 10*eps);
+%!assert (nm2rad (rad2nm (10, "pluto"), "pluto"), 10, 10*eps);
+
+%!error <RADIUS> rad2nm (5, 5i)
diff --git a/inst/rad2sm.m b/inst/rad2sm.m
new file mode 100644
index 0000000..917e758
--- /dev/null
+++ b/inst/rad2sm.m
@@ -0,0 +1,62 @@
+## Copyright (C) 2014-2020 Pooja Rao
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+##
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+##
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {@var{sm} =} rad2sm (@var{rad})
+## @deftypefnx {Function File} {@var{sm} =} rad2sm (@var{rad}, @var{radius})
+## @deftypefnx {Function File} {@var{sm} =} rad2sm (@var{rad}, @var{sphere})
+## Converts angle in radians to distance in statute miles by multiplying angle
+## with radius.
+##
+## Calculates the distances @var{sm} in a sphere with @var{radius} (also in
+## statute miles) for the angles @var{rad}.  If unspecified, radius defaults to
+## 3958 sm, the mean radius of Earth.
+##
+## Alternatively, @var{sphere} can be one of "sun", "mercury", "venus", "earth",
+## "moon", "mars", "jupiter", "saturn", "uranus", "neptune", or "pluto", in
+## which case radius will be set to that object's mean radius.
+##
+## @seealso{deg2km, deg2nm, deg2sm, km2rad, km2deg,
+## nm2deg, nm2rad, rad2km, rad2nm, sm2deg, sm2rad}
+## @end deftypefn
+
+## Built with insight from
+## Author: Pooja Rao <poojarao12@gmail.com>
+## Adapted from deg2km.m by Anonymous contributor, see patch #9709
+
+function sm = rad2sm (rad, radius = "earth")
+
+  ## Check arguments
+  if (nargin < 1 || nargin > 2)
+    print_usage();
+  elseif (ischar (radius))
+    ## Get radius of sphere with its default units (km)
+    radius = km2sm (spheres_radius (radius));
+  ## Check input
+  elseif (! isnumeric (radius) || ! isreal (radius))
+    error ("rad2sm: RADIUS must be a numeric scalar");
+  endif
+  sm = (rad * radius);
+
+endfunction
+
+
+%!test
+%!assert (sm2rad (rad2sm (10)), 10, 10*eps);
+%!assert (sm2rad (rad2sm (10, 80), 80), 10, 10*eps);
+%!assert (sm2rad (rad2sm (10, "pluto"), "pluto"), 10, 10*eps);
+
+%!error <RADIUS> rad2sm (5, 5i)
diff --git a/inst/radtodeg.m b/inst/radtodeg.m
index 1685f40..ad9b7e0 100644
--- a/inst/radtodeg.m
+++ b/inst/radtodeg.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/rasterclip.m b/inst/rasterclip.m
new file mode 100644
index 0000000..d2ea08f
--- /dev/null
+++ b/inst/rasterclip.m
@@ -0,0 +1,129 @@
+## Copyright (C) 2017-2020 Philip Nienhuis
+## 
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*- 
+## @deftypefn {} [@var{rbo}, @var{rio}] = rasterclip (@var{rbi}, @var{rii}, @var{clpbox})
+## Clip a georaster with a rectangle and return adapted bands and info structs.
+##
+## rasterclip is useful for extracting a part of a raster map to enable e.g.,
+## faster drawing 
+## @var{rbi} and @var{rii} are output structs from rasterread.m  @var{clpbox}
+## is a 2x2 matrix containing [Xmin, Ymin; Xmax, Ymax] of the rectangle.
+##
+## Output structs @var{rbo} and @var{rio} contain adapted bbox, data, Width,
+## Height and GeoTransformation fields.  All other fields are copied verbatim,
+## except fields FileSize, FileName and FileModDate which are all left empty.
+##
+## @seealso{rasterread,rasterdraw}
+## @end deftypefn
+
+## Author: Philip Nienhuis <prnienhuis@users.sf.net>
+## Created: 2017-11-01
+
+function [rbo, rio] = rasterclip (rbi, rii, clpbox)
+
+  ## FIXME maybe stricter and more extensive input validation
+  if (nargin < 3 || ! isstruct (rbi) || ! isstruct (rii) || ! ismatrix (clpbox))
+    usage ();
+  endif
+
+  ## Check required fieldnames and remove required (processed) ones from lists
+  fldsr = fieldnames (rbi(1));
+  reqr = {"bbox", "data"};
+  if (! all (ismember (reqr, fldsr)))
+    error ("rasterclip: arg#1: missing fields, improper band struct");
+  endif
+  fldsr (ismember (fldsr, reqr)) = [];
+  
+  fldsi = fieldnames (rii);
+  reqi = {"GeoTransformation", "Width", "Height", "nbands", "BitDepth"};
+  if (! all (ismember (reqi, fldsi)))
+    error ("rasterclip: arg#2: missing fields, improper band struct");
+  endif
+  fldsi(ismember (fldsi, reqi)) = [];
+
+%  ## Check clip rectangle
+%  if (! (issquare (clpbox) && numel (clpbox) != 4) || ...
+%      clpbox(1, 1) >= clpbox(2, 1) || clpbox(2, 1) >= clpbox(2, 2))
+%    error: ("rasterclip: 2x2 array [Xmin Ymin; Xmax Ymax] expected");
+%  endif
+
+  rbox = rii.bbox;
+  clpbox(1, 1) = max (clpbox(1, 1), rbox(1, 1));
+  clpbox(2, 1) = min (clpbox(2, 1), rbox(2, 1));
+  clpbox(1, 2) = max (clpbox(1, 2), rbox(1, 2));
+  clpbox(2, 2) = min (clpbox(2, 2), rbox(2, 2));
+  if (any (! isfinite (clpbox)))
+    error ("One or more of clpbox coordinates outside raster");
+  endif
+
+  ## Check if clpbox endpoints lie within raster
+  rbox = [rbox(1, 1) rbox(1, 2); ...
+          rbox(2, 1) rbox(1, 2); ...
+          rbox(2, 1) rbox(2, 2); ...
+          rbox(1, 1) rbox(2, 2); ...
+          rbox(1, 1) rbox(1, 2)];
+  [inp, onp] = inpolygon (clpbox(:, 1), clpbox(:, 2), rbox(:, 1), rbox(:, 2));
+
+  ## Clip clpbox endpoints to pixel borders
+  xpx = [rbox(1, 1) : ((rbox(2, 1) - rbox(1, 1)) / rii.Width)  : rbox(2, 1)];
+  ypx = [rbox(1, 2) : ((rbox(3, 2) - rbox(1, 2)) / rii.Height) : rbox(3, 2)];
+  irl = find (clpbox(1, 1) <= xpx)(1);
+  irr = find (clpbox(2, 1) >= xpx)(end);
+  irb = find (clpbox(1, 2) <= ypx)(1);
+  irt = find (clpbox(2, 2) >= ypx)(end);
+  
+  ## Copy band struct fields over
+  for jj=1:rii.nbands
+    for ii=1:numel (fldsr)
+      rbo(jj).(fldsr{ii}) = rbi(jj).(fldsr{ii});
+    endfor
+    ## Adapt required fields
+    rbo(jj).bbox(1, 1) = xpx(irl);
+    rbo(jj).bbox(2, 1) = xpx(irr);
+    rbo(jj).bbox(1, 2) = ypx(irb);
+    rbo(jj).bbox(2, 2) = ypx(irt);
+    rbo(jj).data = rbi(jj).data(irb:irt-1, irl:irr-1);
+  endfor
+
+  ## Copy info struct fields over
+  for ii=1:numel (fldsi)
+    rio.(fldsi{ii}) = rii.(fldsi{ii});
+  endfor
+  rio.BitDepth = rii.BitDepth;
+  ## Adapt required fields
+  ## Geotransformation: right-left or left-right 
+  rio.GeoTransformation = rii.GeoTransformation;
+  if (rio.GeoTransformation(2) > 0)
+    rio.GeoTransformation(1) = xpx(irl);
+  else
+    rio.GeoTransformation(1) = xpx(irr);
+  endif
+  ## Top-down or bottom-up
+  if (rio.GeoTransformation(6) < 0)
+    rio.GeoTransformation(4) = ypx(irt);
+  else
+    rio.GeoTransformation(4) = ypx(irb);
+  endif
+  rio.Width       = irr - irl;
+  rio.Height      = irt - irb;
+  rio.nbands      = rii.nbands;
+  rio.bbox        = rbo.bbox;
+  rio.Filename    = "";
+  rio.Filesize    = [];
+  rio.FileModDate = "";
+
+endfunction
diff --git a/inst/rasterdraw.m b/inst/rasterdraw.m
index 7723a08..88999ce 100644
--- a/inst/rasterdraw.m
+++ b/inst/rasterdraw.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2015 Philip Nienhuis
+## Copyright (C) 2015-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
@@ -199,5 +199,6 @@ will be drawn\n", ibands(1));
   endif
   set (gca, "YDir", "normal");
   axis equal;
+  axis tight;
 
 endfunction
diff --git a/inst/rasterinfo.m b/inst/rasterinfo.m
index 8aa1f24..5c3b8df 100644
--- a/inst/rasterinfo.m
+++ b/inst/rasterinfo.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2015 Philip Nienhuis
+## Copyright (C) 2015-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
@@ -54,12 +54,29 @@ function [rinfo] = rasterinfo (fname)
   [rstatus, binfo] = gdalread (fname, 0);
   if (! rstatus)
     ## Check if we have a geotiff file. If so, get extra info
-    if (strcmpi (binfo.FileType, 'geotiff'))
+    if (strcmpi (binfo.FileType, "geotiff"))
       rinfo = imfinfo (fname);
       rinfo.FileType = binfo.FileType;
       rinfo.datatype_name = binfo.datatype_name;
       rinfo.GeoTransformation = binfo.GeoTransformation;
       rinfo.Projection = binfo.Projection;
+      rinfo.nbands = binfo.nbands;
+      if (isfield (binfo, "bbox"))
+        rinfo.bbox = binfo.bbox;
+      else
+        gt = binfo.GeoTransformation;
+        rinfo.bbox = zeros (2);
+        rinfo.bbox(1, 1) = gt(1);
+        rinfo.bbox(2, 1) = gt(1) + (binfo.Width * gt(2)) + (binfo.Height * gt(3));
+        if (gt(2) < 0)
+          rinfo.bbox(:, 1) = flipud (rinfo.bbox(:, 1));
+        endif
+        rinfo.bbox(1, 2) = gt(4);
+        rinfo.bbox(2, 2) = gt(4) + (binfo.Height * gt(6)) + (binfo.Width * gt(5));
+        if (gt(6) < 0)
+          rinfo.bbox(:, 2) = flipud (rinfo.bbox(:, 2));
+        endif
+      endif
     else
       rinfo = binfo;
       rinfo.Filename = canonicalize_file_name (fname);
diff --git a/inst/rasterread.m b/inst/rasterread.m
index 422a9af..ca24a26 100644
--- a/inst/rasterread.m
+++ b/inst/rasterread.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2015 Philip Nienhuis
+## Copyright (C) 2015-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
@@ -27,7 +27,7 @@
 ## (if present for the band) a GDAL colortable (see GDAL on-line
 ## reference).
 ##
-## Outpur argument @var{binfo} contains various info of the raster file:
+## Output argument @var{binfo} contains various info of the raster file:
 ## overall bounding box, geotransformation, projection, size, nr. of columns
 ## and rows, datatype, nr. of bands.
 ##
diff --git a/inst/rcurve.m b/inst/rcurve.m
new file mode 100644
index 0000000..acceb88
--- /dev/null
+++ b/inst/rcurve.m
@@ -0,0 +1,193 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSEll. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{r} =} rcurve (@var{spheroid}, @var{lat})
+## @deftypefnx {Function File} {@var{r} =} rcurve (@var{type}, @var{spheroid}, @var{lat})
+## @deftypefnx {Function File} {@var{r} =} rcurve (@dots{}, @var{angleUnit})
+## Return the length of a curve based on its type: meridian, parallel, or
+## transverse.
+##
+## Optional input argument @var{type} is one of "meridian", "parallel", or
+## "transverse; default (when left empty or skipped) is "parallel".
+## @var{spheroid} is the spheroid of choice (default: "wgs84").  @var{lat}
+## is the latitude at which the curve length should be computed and can be
+## a numeric scalar, vector or matrix.  Output argument @var{r} will have the
+## same size and dimension(s) as @var{lat}.
+##
+## Optional input argument @var{angleUnit} can be either "radians" or "degrees"
+## (= default); just "r" or "d" will do.  All character input is
+## case-insensitive.
+##
+## Examples:
+##
+## @example
+## r = rcurve ("parallel", "wgs84", 45)
+## => r =
+## 4.5176e+06
+## Note: this is in meters
+## @end example
+##
+## @example
+## r = rcurve ("", 45)
+## => r =
+## 4.5176e+06
+## @end example 
+##
+## @example
+## r = rcurve ("", "", 45)
+## => r =
+## 4.5176e+06
+## @end example
+##
+## @example
+## r = rcurve ("", "", pi/4, "radians")
+## => r =
+## 4.5176e+06
+## @end example
+##
+## @example
+## r = rcurve ("meridian", "wgs84", 45)
+## => r =
+## 6.3674e+06
+## @end example
+##
+## @example
+## r = rcurve ("transverse", "wgs84", 45)
+## => r =
+## 6.3888e+06
+## @end example
+##
+## Also can use structures as inputs:
+## @example
+## r = rcurve("", referenceEllipsoid ("venus"), 45)
+## => r =
+## 4.2793e+06
+## @end example
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9658
+
+function r = rcurve (varargin)
+
+  if (nargin < 2 || nargin > 4)
+    print_usage ();
+  elseif (nargin == 2)
+    ## Neither type nor angleUnit specified
+    type = "parallel";
+    angleUnit = "degrees";
+    spheroid = varargin{1};
+    lat = varargin{2};
+    ip = 1;
+  elseif (nargin >= 3)
+    if (isnumeric (varargin{2}) && isreal (varargin{2}))
+      ## arg{1} = spheroid, type skipped
+      type = "parallel";
+      ip = 1;
+    elseif (isnumeric (varargin{3}) && isreal (varargin{3}))
+      ## arg{1} = type, no angleunit given
+      angleUnit = "degrees";
+      ip = 0;
+    else
+      error ("rcurve.m : real numeric input expected for Lat");
+    endif
+    type = varargin{ip + 1};
+    spheroid = varargin{ip + 2};
+    lat = varargin{ip + 3};
+  endif
+  if (nargin == 4)
+    if (ischar (varargin{4}))
+      angleUnit = varargin{4};
+    else
+      error ("rcurve.m : 'degrees' or 'radians' expected for angleUnits");
+    endif
+  endif
+
+  if isempty (type)
+    type = "parallel";
+  endif
+
+  if isempty (spheroid)
+    E = wgs84Ellipsoid;
+  elseif (isstruct (spheroid))
+    E = spheroid;
+  else
+    E = referenceEllipsoid (spheroid);
+  endif 
+
+  if (! ischar (angleUnit) || ! ismember (lower (angleUnit(1)), {"d", "r"}))
+    error ("rcurve.m: angleUnit should be one of 'degrees' or 'radians'")
+  endif
+
+  if (strncmpi (lower (angleUnit), "r", 1) == 1)
+    c_l = cos (lat);
+    s_l = sin (lat);
+  else
+    c_l = cosd (lat);
+    s_l = sind (lat);
+  endif
+
+  ## Insight From: Algorithms for Global Positioning pg 370-372
+
+  e2 = E.Eccentricity ^ 2;
+  R = E.SemimajorAxis;
+  e_p = e2 / (1 - e2);
+
+  N = (R * sqrt ( 1 + e_p) ./ (sqrt (1 + e_p * c_l .^ 2)));
+  switch type
+    case {"meridian"}
+      w = sqrt (1 - e2 .* s_l .^ 2);
+      r = R * (1 - e2 ) ./ (w .^ 3);
+    case {"parallel"}
+      r = N .* c_l;
+    case {"transverse"}
+      r = N;
+    otherwise
+      error ("rcurve: type should be one of'meridian', 'parallel', or 'transverse'")
+  endswitch
+  
+endfunction
+
+
+%!test
+%! assert (rcurve ("", 45), 4517590.87885, 10e-6)
+
+%% Row vector
+%!test
+%! assert (rcurve ("", [45; 20]), [4517590.87885; 5995836.38390], 10e-6)
+
+%% Column vector
+%!test
+%! assert (rcurve ("", [45, 20]), [4517590.87885, 5995836.38390], 10e-6)
+
+%% Matrix
+%!test
+%! assert (rcurve ("", [60 45; 35 20]), [3197104.58692, 4517590.87885; 5230426.84020, 5995836.38390], 10e-6)
+
+%!test
+%! assert (rcurve ("", "", 45), 4517590.87885, 10e-6)
+
+%!test
+%! assert (rcurve ("transverse", "", 45), 6388838.29012, 10e-6)
+
+%!test
+%! assert (rcurve ("meridian", "", 45), 6367381.81562, 10e-6)
+
+%!error <angleUnit> rcurve ("","", 45, "km")
+%!error <numeric input expected>  rcurve ("", "", "A")
+%!error <numeric input expected>  rcurve ("", "", 45i)
+%!error <type> rcurve ('All', "", 45)
diff --git a/inst/reckon.m b/inst/reckon.m
index bfd154d..090ec57 100644
--- a/inst/reckon.m
+++ b/inst/reckon.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2008 Alexander Barth <abarth93@users.sourceforge.net>
+## Copyright (C) 2008-2020 Alexander Barth <abarth93@users.sourceforge.net>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
diff --git a/inst/referenceEllipsoid.m b/inst/referenceEllipsoid.m
new file mode 100644
index 0000000..c7b819e
--- /dev/null
+++ b/inst/referenceEllipsoid.m
@@ -0,0 +1,349 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSEll. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} referenceEllipsoid (@var{name}, @var{unit})
+## Returns the parameters of an ellipsoid.
+##
+## @var{Name} can be the name (e.g., "wgs84") or (integer) EPSG code of a
+## reference ellipoid.  Case is not important.  If the number or code 0
+## (zero) is specified, referenceEllipsoid echoes a list of implemented
+## ellipsoids to the screen.
+##
+## @var{unit} can be the name of any unit accepted by function 
+## validateLengthUnit.m.  Also here case is not important.
+##
+## The output consists of a scalar struct with fields "Code" (EPSG code of the
+## ellipsoid), "Name" (name of the ellipsoid), "LengthUnit", "SemimajorAxis",
+## "SemiminorAxis", "InverseFlattening", "Eccentricity", "Flattening", 
+## "ThirdFlattening", "MeanRadius", "SurfaceArea", and "Volume".
+##
+## Examples:
+##
+## @example
+## >> E = referenceEllipsoid ("wgs84")
+## E =
+##
+##  scalar structure containing the fields:
+##
+##    Code =  7030
+##    Name = World Geodetic System 1984
+##    LengthUnit = meter
+##    SemimajorAxis =  6378137
+##    SemiminorAxis =    6.3568e+06
+##    InverseFlattening =  298.26
+##    Eccentricity =  0.081819
+##    Flattening =  0.0033528
+##    ThirdFlattening =  0.0016792
+##    MeanRadius =    6.3710e+06
+##    SurfaceArea =    5.1007e+14
+##    Volume =    1.0832e+21
+## @end example
+##
+## The code number can be used:
+##
+## @example
+## >> E = referenceEllipsoid (7019)
+## E = 
+##
+##  scalar structure containing the fields:
+##
+##    Code =       7019
+##    Name = Geodetic Reference System 1980
+##    LengthUnit = meter
+##    SemimajorAxis = 6.3781e+06
+##    SemiminorAxis = 6.3568e+06
+##    InverseFlattening =     298.26
+##    Eccentricity =   0.081819
+##    Flattening =  0.0033528
+##    ThirdFlattening =  0.0016792
+##    MeanRadius =  6.371e+06
+##    SurfaceArea = 5.1007e+14
+##    Volume = 1.0832e+21
+## @end example
+##
+## @example
+## >> E = referenceEllipsoid ("wgs84", "km")
+## E =
+##
+##  scalar structure containing the fields:
+##
+##    Code =  7030
+##    Name = World Geodetic System 1984
+##    LengthUnit = km
+##    SemimajorAxis =  6378.1
+##    SemiminorAxis =  6356.8
+##    InverseFlattening =  298.26
+##    Eccentricity =  0.081819
+##    Flattening =  0.0033528
+##    ThirdFlattening =  0.0016792
+##    MeanRadius =  6371.0
+##    SurfaceArea =    5.1007e+08
+##    Volume =    1.0832e+12
+## @end example
+##
+## @seealso{validateLengthUnit, wgs84Ellipsoid}
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9634
+
+function Ell = referenceEllipsoid (name="wgs84", unit="meter")
+
+  ## List of implemented codes. To be updated if codes are added.
+  persistent codes;
+  if (isempty (codes))
+    codes = {"7001", "Airy30",       " "; ...
+             "7002", "Airy49",       " "; ...
+             "7003", "Australia",    " "; ...
+             "7004", "Bessel",       " "; ...
+             "7008", "Clarke66",     " "; ...
+             "7012", "Bessel 1880",  " "; ...
+             "7015", "Everest 1830", " "; ...
+             "7019", "grs80",        "1980"; ...
+             "7022", "int24",        "1924"; ...
+             "7024", "Kras40",       "Krasovsky"; ...
+             "7030", "Wgs84",        "1984"; ...
+             "7043", "Wgs72",        "1972"; ...
+             " ",    "Sun",          " "; ...
+             " ",    "Mercury",      " "; ...
+             " ",    "Venus",        " "; ...
+             " ",    "Earth",        " "; ...
+             " ",    "Moon",         " "; ...
+             " ",    "Mars",         " "; ...
+             " ",    "Jupiter",      " "; ...
+             " ",    "Saturn",       " "; ...
+             " ",    "Uranus",       " "; ...
+             " ",    "Neptune",      " "; ...
+             " ",    "Pluto",        " "};
+  endif
+
+  if (isnumeric (name) && isreal (name))
+    name = num2str (fix (name));
+  elseif (! ischar (name))
+    error ("referenceEllipsoid: value must be a string or real number");
+  elseif (strcmp (name, " "))
+    error ("referenceEllipsoid: name required");
+  endif
+
+  if (! ischar (unit))
+    error ("referenceEllipsoid: length name expected for input arg. #2");
+  endif
+
+  switch lower (name)
+    ## Semimajor axis and Inverse flattening from
+    ## USER's HANDBOOK ON DATUM TRANSFORMATIONS INVOLVING WGS 84
+    ## 3rd Edition, July 2003, (Last correction August 2008),
+    ## Special Publication No. 60
+    ## Codenames are from https://epsg.io/
+    ## Planet values from Report of the IAU Working Group on
+    ## CartographicCoordinates and Rotational Elements: 2015
+
+    case lower (codes(1, :))
+      Code = 7001;
+      Name = "Airy 1830";
+      SemimajorAxis = 6377563.396;
+      InverseFlattening = 299.3249646;
+        
+    case lower (codes (2, :))
+      Code = 7002;
+      Name = "Airy Modified 1849";
+      SemimajorAxis = 6377340.189;
+      InverseFlattening = 299.3249646;
+
+    case lower (codes (3, :))
+      Code = 7003;
+      Name = "Australian National";
+      SemimajorAxis = 6378160;
+      InverseFlattening = 298.25;
+
+    case lower (codes (4, :))
+      Code = 7004;
+      Name = "Bessel 1841";
+      SemimajorAxis = 6377397.155;
+      InverseFlattening = 299.1528128;
+
+    case lower (codes (5, :))
+      Code = 7008;
+      Name = "Clarke 1866";
+      SemimajorAxis = 6378206.4;
+      InverseFlattening = 294.9786982;
+
+    case lower (codes (6, :))
+      Code = 7012;
+      Name = "Bessel 1880";
+      SemimajorAxis = 6378249.145;
+      InverseFlattening = 293.465;
+
+    case lower (codes (7, :))
+      Code = 7015;
+      Name = "Everest 1830";
+      SemimajorAxis = 6377276.34518;
+      InverseFlattening = 300.8017;
+
+    case lower (codes (8, :))
+      Code = 7019;
+      Name = "Geodetic Reference System 1980";
+      SemimajorAxis = 6378137;
+      InverseFlattening = 298.257222101;
+
+    case lower (codes (9, :))
+      Code = 7022;
+      Name = "International 1924";
+      SemimajorAxis = 6378388;
+      InverseFlattening = 297;
+
+    case lower (codes (10, :))
+      Code = 7024;
+      Name = "Krasovsky 1940";
+      SemimajorAxis = 6378245;
+      InverseFlattening = 298.3;
+
+    case lower (codes (11, :))
+      Code = 7030;
+      Name = "World Geodetic System 1984";
+      SemimajorAxis = 6378137;
+      InverseFlattening = 298.2572235630;
+
+    case lower (codes (12, :))
+      Code = 7043;
+      Name = "World Geodetic System 1972";
+      SemimajorAxis = 6378135;
+      InverseFlattening = 298.26;
+
+    case lower (codes (13, :))
+      Code = " ";
+      Name = "Sun";
+      SemimajorAxis = 695700000;
+      InverseFlattening = 111111;
+
+    case lower (codes (14, :))
+      Code = " ";
+      Name = "Mercury";
+      SemimajorAxis = 2440530;
+      InverseFlattening = 1075;
+
+    case lower (codes (15, :))
+      Code = " ";
+      Name = "Venus";
+      SemimajorAxis = 6051800;
+      InverseFlattening = Inf;
+
+    case lower (codes (16, :))
+      Code = " ";
+      Name = "Earth";
+      SemimajorAxis = 6378137;
+      InverseFlattening = 298.2572235630;
+
+    case lower (codes (17, :))
+      Code = " ";
+      Name = "Moon";
+      SemimajorAxis = 1738100;
+      InverseFlattening = 833.33;
+
+    case lower (codes (18, :))
+      Code = " ";
+      Name = "Mars";
+      SemimajorAxis = 3396190;
+      InverseFlattening =  169.894;
+
+    case lower (codes (19, :))
+      Code = " ";
+      Name = "Jupiter";
+      SemimajorAxis = 71492000;
+      InverseFlattening =  15.4144;
+
+    case lower (codes (20, :))
+      Code = " ";
+      Name = "Saturn";
+      SemimajorAxis = 60268000;
+      InverseFlattening = 10.208;
+
+    case lower (codes (21, :))
+      Code = " ";
+      Name = "Uranus";
+      SemimajorAxis = 25559000;
+      InverseFlattening = 43.616;
+
+    case lower (codes (22, :))
+      Code = " ";
+      Name = "Neptune";
+      SemimajorAxis = 24764000;
+      InverseFlattening = 58.5437;
+
+    case lower (codes (23, :))
+      Code = " ";
+      Name = "Pluto";
+      SemimajorAxis = 1188300;
+      InverseFlattening = INF;
+
+    case "0"
+      ## Show list of codes
+      printf ("\n referenceEllipsoid.m:\n list of implemented ellipsoids:\n");
+      printf (" Code          Alias 1          Alias 2\n");
+      printf (" ====          =======          =======\n");
+      for ii=1:size (codes, 1)
+        printf ("%5s  %15s  %15s\n", codes (ii, :){:});
+      endfor
+      return
+
+    otherwise
+      error ("referenceEllipsoid: ellipsoid %s has not been implemented", name)
+
+  endswitch
+
+  ## Calculations
+  Ell = param_calc (Code, Name, SemimajorAxis, InverseFlattening, unit);
+
+endfunction
+
+
+function ell = param_calc (Code, Name, SemimajorAxis, InvF, unit)
+
+  ell.Code              = Code;
+  ell.Name              = Name;
+  ratio   = unitsratio (unit, "Meters");
+  ell.LengthUnit        = unit;
+  Major   = SemimajorAxis * ratio;
+  ell.SemimajorAxis     = Major;
+  Inverse = InvF;
+  ell.InverseFlattening = InvF;
+  Ecc     = flat2ecc (1 / InvF);
+  ell.Eccentricity      = Ecc;
+  Minor   = minaxis (Major, Ecc);
+  ell.SemiminorAxis     = Minor;
+  ell.Flattening        = 1 / InvF;
+  ell.ThirdFlattening   = (Major - Minor) / (Major + Minor);
+  ell.MeanRadius        = (2 * Major + Minor) / 3;
+  ## From Knud Thomsen this results in a max error of 1.061 %:
+  P       = 1.6075;
+  Surface = 4 * pi * ((Major^(2*P) +  2 * (Major * Minor)^P) / 3 )^(1/P);
+  ell.SurfaceArea       = Surface;
+  ell.Volume            = (4 * pi) / 3 * Major^2 * Minor;
+
+endfunction
+
+
+%!test
+%!
+%! E = referenceEllipsoid ("wgs84");
+%! assert ( E.SemiminorAxis, 6356752.314245, 10e-7 )
+%! assert ( E.Eccentricity, 0.081819221456, 10e-8)
+%! assert ( E.Flattening, 1 / 298.2572235630, 10e-8 )
+
+%!error <value must be a string> referenceEllipsoid ( 7i )
+%!error <not been implemented> referenceEllipsoid ( "yy" )
+%!error <name required> referenceEllipsoid ( " " )
diff --git a/inst/removeExtraNanSeparators.m b/inst/removeExtraNanSeparators.m
index 53ab84e..618af11 100644
--- a/inst/removeExtraNanSeparators.m
+++ b/inst/removeExtraNanSeparators.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/roundn.m b/inst/roundn.m
index 3fb697d..8a35fe6 100644
--- a/inst/roundn.m
+++ b/inst/roundn.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2015 Markus Bergholz <markuman@gmail.com>
+## Copyright (C) 2015-2020 Markus Bergholz <markuman@gmail.com>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
diff --git a/inst/shapedraw.m b/inst/shapedraw.m
index d0221c0..dfeb0fb 100644
--- a/inst/shapedraw.m
+++ b/inst/shapedraw.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014,2015 Philip Nienhuis
+## Copyright (C) 2014-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
@@ -68,48 +68,6 @@
 
 ## Author: Philip Nienhuis <prnienhuis@users.sf.net>
 ## Created: 2014-11-15
-## Updates:
-## 2014-11-15 First draft
-## 2014-11-17 Add support for geostructs
-## 2014-11-29 Solid fill (patches)
-## 2014-12-16 Solid fill (polygons) with holes
-## 2014-12-17 MultiPatch plots (3D)
-## 2014-12-18 3D Points/Polylines/-gons
-## 2014-12-30 Transpose npr values for MultiPatch prior to drawing patches
-## 2015-01-01 Fix function name in error message
-## 2015-01-06 Improve plotting of polygons with holes - optimize branch cuts
-## 2015-01-07 Largely rewritten; 
-##            - Combined line and patch sections into one switch
-##            - More rigorous checks on input parameters
-## 2015-01-08 More rewrites, better input checks
-##     ''     Allow marker indicators for (multi)point
-## 2015-01-09 Add code to check if individual polygon parts are holes (not all)
-##     ''     Improve code for single color code/stle arguments
-## 2015-01-10 Renamed to shapedraw.m (shapeplot is already in OF-geometry)
-##     ''     Fixed argument checking for "color" property (swapping if checks)
-## 2015-01-20 Change "color" to "edgecolor" for multipatch
-##     ''     Add undocumented "center" argument to cope with large coordinates
-##            (OpenGL chokes there as it only works with single precision)
-## 2015-01-21 Apply varargin to 3D-patches using "set" command
-##     ''     Simplify input args, eliminate "clr" arg
-##     ''     Support for extended mapstructs
-## 2015-01-24 Restructured a bit, debugged MultiPatch drawing
-## 2015-01-27 Texinfo header, check on Z-values
-## 2015-01-30 Simplify ML style struct test; allow Point types (no BoundingBox)
-## 2015-01-31 Fix wrong indexing in MultiPatch-triangle processing
-## 2015-02-03 Swap checks for first color arg and graphics properties
-## 2015-02-04 Check for Z and make it a column vector before calling plot3
-##     ''     Morefixes for color argument checks
-## 2015-02-11 Eliminate duplicate code, move to subfunc chk_props
-## 2015-02-17 Markerstyle => Marker in point draw switch stmt
-##     ''     Don't reshape back args in chk_props subfuc
-##     ''     Improve checks for default color
-## 2015-04-19 Make warning state changes local
-## 2015-07-10 Add try-catch around varargin reshape to catch wrong input
-##     ''     Simplify polygon plot code
-##     ''     Fix 3D-plotting for "extended" map/geostructs
-## 2015-12-27 Improve speed of drawing many polygons
-## 2015-12-30 Improve multipatch drawing speed
 
 function [h] = shapedraw (shpf, varargin)
 
@@ -140,11 +98,6 @@ function [h] = shapedraw (shpf, varargin)
     ## Nothing to plot
     return;
 
-  if (isempty (varargin))
-    ## Supply default color
-    varargin = {[0.6, 0.6, 0.6]};
-  endif
-
   elseif (isstruct (shpf))
     ## Yep. Find out what type
     fldn = fieldnames (shpf);
@@ -183,6 +136,11 @@ function [h] = shapedraw (shpf, varargin)
     error ("struct name of file name expected");
   endif
 
+  if (isempty (varargin))
+    ## Supply default color
+    varargin = {[0.6, 0.6, 0.6]};
+  endif
+
   ## 2. Morph XY[Z} data in a suitable form for fastest plotting
 
   ## Prepare XY plot. Get vertices & prepare some geometry data
@@ -389,7 +347,7 @@ function [h] = shapedraw (shpf, varargin)
         endif
         varargin = {"edgecolor", varargin{1}(1, :) "facecolor" varargin{1}(2, :)};
       else
-        varargin = {"color" clr(1, :) varargin{:}};
+        varargin = {"color", varargin{:}};
       endif
     endif
   endif
@@ -421,7 +379,7 @@ function [h] = shapedraw (shpf, varargin)
       ## Check for some marker style or marker color code (latter always arg #1)
       if (! ismember ("marker", lower (varargin(1, :))) && ...
           ! ismember (varargin(1), color_codes))
-        varargin = { "marker", "." varargin{:} };
+        varargin = { "marker", ".", "linestyle", "none" varargin{:} };
       endif
       plot (X, Y, varargin{:});
 
@@ -430,7 +388,7 @@ function [h] = shapedraw (shpf, varargin)
       ## Check for some marker style or marker color code (latter always arg #1)
       if (! ismember ("marker", lower (varargin(1, :))) && ...
           ! ismember (varargin(1), color_codes))
-        varargin = {"marker", "." varargin{:} };
+        varargin = {"marker", ".", "linestyle", "none" varargin{:} };
       endif
       plot3 (X, Y, Z, varargin{:});
 
diff --git a/inst/shapeinfo.m b/inst/shapeinfo.m
index b11e040..694f730 100644
--- a/inst/shapeinfo.m
+++ b/inst/shapeinfo.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014,2015 Philip Nienhuis
+## Copyright (C) 2014-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
@@ -89,6 +89,9 @@ function [infs] = shapeinfo (fname)
 
   ## Start reading header
   fidp = fopen (fname, 'r');
+  if (fidp < 0)
+    error ("shapeinfo: can't open file %s\n", fname);
+  endif
   fseek (fidp, 0, "bof");
 
   ## Read & check file code
@@ -143,9 +146,12 @@ function [infs] = shapeinfo (fname)
   endif
 
   fclose (fidp);
+  finfo =  dir (fname);
 
   ## Return info
   infs.NumFeatures = recn;
+  infs.FileSize = finfo.bytes;
+  infs.LastModified = datestr (finfo.datenum, 0);
 
   ## ====================== 3. .dbf ======================
   
diff --git a/inst/shaperead.m b/inst/shaperead.m
index 7968730..39325b0 100644
--- a/inst/shaperead.m
+++ b/inst/shaperead.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014,2015 Philip Nienhuis
+## Copyright (C) 2014-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
@@ -47,7 +47,7 @@
 ## @itemx  e
 ## Same as 1 but M and Z type and MultiPatch shape features are accepted.  The
 ## resulting output struct is no more ML-compatible.  If the shapefile contains
-## M and/or Z type shape features the mapstruct or gestruct has extra fields M
+## M and/or Z type shape features the mapstruct or geostruct has extra fields M
 ## and -optionally- Z.  Note that MultiPatch shape features may not have
 ## M-values even if Z-values are present.  For MultiPatch shapes another field
 ## Parts is added, a Px2 array with zero-based indices to the first vertex of
@@ -97,6 +97,13 @@
 ## characters are significant, case doesn't matter):
 ##
 ## @table @code
+## @item Attributes
+## Normally all attributes associated with the shape features will be read
+## and returned in the output struct(s).  To limit this to just some
+## attributes, enter a value consisting of a cell array of attribute names to
+## be read.  To have no attributes read at all, specify @{@}, an empty cell
+## array.
+##
 ## @item BoundingBox
 ## Select only those shape items (features) whose bounding box lies within, or
 ## intersets in at least one point with the limits of the BoundingBox value (a
@@ -105,18 +112,20 @@
 ## default!
 ##
 ## @item Clip
-## (only useful in conjuction with the BoundingBox property) If a value of 1 or
-## true is supplied, clip all shapes to the bounding box limits.  This option
-## may take quite a bit of processing time.  If a value of "0" or false is
-## given, do not perform clipping.  The default value is 0.
+## (only useful in conjuction with the BoundingBox property) If a value of 1
+## or true is supplied, clip all shapes to the bounding box limits.  This
+## option may take quite a bit of processing time.  If a value of "0" or false
+## is given, do not perform clipping.  The default value is 0.
 ## Clipping is merely meant to be performed in the XY plane.  Clipping 3D
-## shapes may work to some extent but can lead to unpredictable results; this
-## is especially true for MultiPatch shape types.
-## For M and Z type polylines and polygons, the M and Z values are linearly
-## interpolated for segments crossing the bounding box.  As no M and Z values
-## can be computed for "new" corner nodes, NaN values are inserted there.
-## For clipping polylines and polygons the Octave-Forge geometry and octclip 
-## packages need to be installed and loaded.
+## shapes is supported but may lead to unexpected results.
+## For Z and M type polylines and polygons including MultiPatch and
+## Longitude/Latitude/Height types, Z (Height) and M values for each vertex in
+## the clipped shape feature are simply copied over from the nearest vertex in
+## the original shape feature.  This implies that Z and M values of new
+## vertices created on the bounding box edges may be less optimal.
+##
+## For clipping polylines and polygons the Octave-Forge geometry package needs
+## to be installed and loaded.
 ## 
 ## @item Debug
 ## If a value of 'true' or 1 is given, shaperead echoes the current record
@@ -134,55 +143,18 @@
 ## (Only applicable if a Matlab-style output struct is requested). If a value
 ## of 'true' (or 1) is supplied, return a geostruct rather than a mapstruct.
 ## If a value of 0 or false is given, return a mapstruct.
-## The mere difference is that in a geostruct the fields 'X' and 'Y' are
-## replaced by 'Long' and 'Lat'. The default value is 'false' (return a
-## mapstruct').
+## The mere difference is that in a geostruct the fields 'X' and 'Y' (and
+## optionally 'Z') are replaced by 'Long' and 'Lat' (and 'Hght').  The
+## default value is 'false' (return a mapstruct').
 ## @end table
 ##
+## Ref: http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf
+##
 ## @seealso{geoshow, mapshow, shapedraw, shapeinfo}
 ## @end deftypefn
 
 ## Author: Philip Nienhuis <prnienhuis@users.sf.net>
 ## Created: 2014-11-07
-## Updates:  **** FIXME Please leave this until the next mapping package release ***
-## 2014-11-07/10  First draft
-## 2014-11-12 Rewrite into more logical struct array
-## 2014-11-13 Fix indexing in NaN row insertion for outopts=1
-## 2014-11-14 Added Matlab-compatible output mapstruct option
-## 2014-11-15 Removed redundant code leading to a 75 X speed increase
-##     ''     Fix ML-style X and Y coordinates
-## 2014-11-16 Add shape type to each struct element for ML-style output
-##     ''     Initial input options parsing
-##     ''     RecordNumbers, UseGeoCoords and BoundingBox implemented
-## 2014-11-17 Double output structs (ML-compatible)
-## 2014-11-18 Polygon clipping & test for geometry package
-## 2014-11-26 Polygon clipping debugged & working
-## 2014-11-28 Return empty cell arr if no shape features read
-##     ''     Return full mapstruct array for no output arg
-## 2014-11-29 Doubly run inpolygon to include features > and < BoundingBox
-## 2014-11-30 Implement Polygon & Point clipping
-## 2014-12-15 Last debug of Polyline clipping
-## 2014-12-17 Fix MultiPatch reading, esp. detection of missing M (measure)
-## 2014-12-29 Implement selecting cellstr attributes in .dbf file
-## 2014-12-30 Do not transpose npr values for MultiPatch
-## 2015-01-01 Catch null shapes and prevent reading their attributes
-## 2015-01-10 Use .shx (if present) to speed up RecordNumbers searches
-## 2015-01-12 For outopts=1, apply cell2mat to numeric & logical attributes
-## 2015-01-14 Swap outopts values for ml (now 0) and plt style (now 3). In
-##            passing, fix wrong switch case id at ~L.651.
-##     ''     Reserve outopts = 1 for future use (ML-comp. mapstruct w. Z & M
-##            atts & multipatch feature type
-## 2015-01-19 Do not include/process NULL shape types once record has been read
-## 2015-01-27 Stricter checks on ML compatibility for outopts=1; fix some
-##            wrong references to outopts type, add ext/e for outopts=1; 
-##            update texinfo header; speed-up reading MultiPatch
-## 2015-04-19 Make warning setting local
-##     ''     Add filesep to basename
-## 2015-07-10 Separate checks for octclip and geometry package
-##     ''     Make rest of warning settings local
-##     ''     Avoid leading filesep in case of no full path name in basename
-##     ''     Improve struct type check and error message
-##       **** FIXME Please leave this until the next mapping package release ***
 
 function [ outs, oatt ] = shaperead (fname, varargin);
 
@@ -215,59 +187,75 @@ function [ outs, oatt ] = shaperead (fname, varargin);
     outopts = 0;
   elseif (nargin == 2)
     ## Assume filename + outopts was supplied
-    outopts = varargin{1};
+    if (isempty (varargin{1}))
+      ## Assume ML-style output
+      outopts = 0;
+    else
+      outopts = varargin{1};
+    endif
     varargin = {};
   elseif (rem (nargin, 2) == 0)
     ## Even number of input args => Outopts & at least one pair of varargin
     outopts = varargin{1};
     varargin(1) = [];
   else
-    ## Only filename and varargin supplied
-    outopts = 0;
-    ## Just to be sure check, if output type was selected anyway; it would
-    ## imply a missing opts value
-    if (any (strncmp (varargin{1}, {"ml", "ext", "oct", "dat"}, 1)) || ...
-        isnumeric (varargin{1}))
-      outopts = varargin{1};
-      varargin(1) = [];
+    ## Odd nr; maybe only filename and prop/val(s) supplied, outstyle skipped
+    if (ischar (varargin{1}))
+      ## Check arg#2, must be a property name then
+      if (! ismember (lower (varargin{1}(1:min(3, numel (varargin{1})))), ...
+                          {"att", "bou", "cli", "deb", "rec", "sel", "use"}))
+        error ("shaperead: property name expected for arg. #2");
+      endif
+    else
+      ## no outstyle or property => wrong input
+      print_usage ();
     endif
+    outopts = 0;
   endif
 
   ## Check output type arg
   if (isnumeric (outopts))
     if (outopts < 0 || outopts > 3)
-      error ("shaperead: value for arg. #2 out of range 0-3\n");
+      error ("shaperead: arg. #2 integer value out of range 0-3\n");
     endif
   elseif (ischar (outopts))
     outopts = lower (outopts);
     if (! any (strncmp (outopts, {"ml", "ext", "oct", "dat"}, 1)))
-      error ("shaperead: value for arg. #2 should be one of 'ml', 'ext', 'oct' or 'dat'\n");
+      error ("shaperead: arg. #2 char value should be one of 'ml', 'ext', \
+'oct' or 'dat'\n");
     endif
     switch outopts
       case {"ml", "m"}
         outopts = 0;
       case {"ext", "e"}
-        outopts = 0;
+        outopts = 1;
       case {"oct", "o"}
         outopts = 2;
       case {"dat", "d"}
         outopts = 3;
       otherwise
-        error ("shaperead: illegal value for arg. #2: '%s' - expected 'ml', 'ext', 'oct' of 'dat'", ...
+        error ("shaperead: illegal value for arg. #2: '%s' - expected 'ml', \
+'ext', 'oct' of 'dat'", ...
                outopts);
     endswitch
   else
     error ("shaperead: numeric or character type expected for arg. #2\n");
   endif
 
-  ## ---------------------- 1. .shx ----------------------
-
+  ## Check .shp file existence
+  fidp = fopen (fname, "r");
+  ## Postpone file opening error until after other provisional input validation
+  if (fidp > 0)
+    ## Temporarily close to avoid file handle leaks during further input checks
+    fclose (fidp);
+  endif
+  ## - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   ## Open .shx file to help speed up seeks to next records. We need this info
   ## for s_recs check below
   have_shx = 0;
   fidx = fopen ([bname ".shx"], "r");
   if (fidx < 0)
-    warning ("shaperead: index file %s not found\n", [fnm ".shx"]);
+    s_recs = [];
   else
     fseek (fidx, 24, "bof");
     fxlng = fread (fidx, 1, "int32", 72, "ieee-be");
@@ -278,79 +266,86 @@ function [ outs, oatt ] = shaperead (fname, varargin);
     fclose (fidx);
     ## Get indices & lengths in bytes
     ridx *= 2;
+    have_shx = 1;
+    s_recs = [1 : size(ridx, 1)];
   endif
 
   ## Parse options; first set defaults
   clip = 0;
   dbug   = 0;
-  s_atts = {};
+  s_atts = [];
   s_bbox = [];
   s_geo  = 0;
-  s_recs = [];
   ## Init collection of records that meet BB criteria
   bb_union = [];
   ## Process input args
   for ii = 1:2:length (varargin)
-    switch (lower (varargin{ii})(1:3))
-      case "att"
-        ## Select records based on attribute values
-        s_atts = varargin{ii+1};
-      case "bou"
-        ## Select whether record / shape feature points lie inside or outside limits
-        try
-          s_bbox = double (varargin{ii+1});
-          if (numel (s_bbox) != 4)
-            error ("shaperead: 2 X 2 numeric array expected for BoundingBox\n");
-          endif
-        catch
-          error ("shaperead: numeric2 X 2 array expected for BoundingBox\n");
-        end_try_catch
-        ## Initialize supplementary polygon array here
-        sbox = [s_bbox(1) s_bbox(2); s_bbox(1) s_bbox(4); s_bbox(3) s_bbox(4); ...
-                s_bbox(3) s_bbox(2); s_bbox(1) s_bbox(2)];
-      case "cli"
-        ## Clip polygons to requested BoundingBox
-        try
-          clip = logical (varargin{ii+1});
-        catch
-          error ("numeric or logical value expected for 'Clip'\n");
-        end_try_catch
-      case "deb"
-        ## Set verbose output (count records)
-        try
-          dbug = logical (varargin{ii+1});
-        catch
-          error ("numeric or logical value expected for 'Debug'\n");
-        end_try_catch
-      case "rec"
-        ## Select record nrs directly. Check for proper type & clean up
-        try
-          s_recs = sort (unique (double (varargin{ii+1}(:))));
-          have_shx = fidx > 0;
-          if (have_shx && any (s_recs > nrec))
-            printf ("shaperead: requ. record nos. > nr. of records (%d) ignored\n", ...
-                    nrec);
-            s_recs (find (srecs > nrec)) = [];
+    if (! ischar (varargin{ii}))
+      error ("shaperead: property %d: property name expected but got a %s value", ...
+              (ii+1)/2, class (varargin{ii}));
+    elseif (numel (varargin{ii}) < 3)
+      warning ("shaperead: unknown option '%s' - ignored\n", varargin{ii});
+    else
+      switch (lower (varargin{ii})(1:3))
+        case "att"
+          ## Select records based on attribute values
+          s_atts = varargin{ii+1};
+        case "bou"
+          ## Select whether record/shape features partly lie inside or outside limits
+          try
+            s_bbox = double (varargin{ii+1});
+            if (numel (s_bbox) != 4)
+              error ("shaperead: 2 X 2 numeric array expected for BoundingBox\n");
+            endif
+          catch
+            error ("shaperead: numeric 2 X 2 array expected for BoundingBox\n");
+          end_try_catch
+          ## Initialize supplementary polygon array here
+          sbox = [s_bbox(1) s_bbox(3); s_bbox(2) s_bbox(3); s_bbox(2) s_bbox(4); ...
+                  s_bbox(1) s_bbox(4); s_bbox(1) s_bbox(3)];
+        case "cli"
+          ## Clip polygons to requested BoundingBox
+          try
+            clip = logical (varargin{ii+1});
+          catch
+            error ("numeric or logical value expected for 'Clip'\n");
+          end_try_catch
+        case "deb"
+          ## Set verbose output (count records)
+          try
+            dbug = logical (varargin{ii+1});
+          catch
+            error ("numeric or logical value expected for 'Debug'\n");
+          end_try_catch
+        case "rec"
+          ## Select record nrs directly. Check for proper type & clean up
+          try
+            s_recs = sort (unique (double (varargin{ii+1}(:))));
+            if (have_shx && any (s_recs > nrec))
+              printf ("shaperead: requ. record nos. > nr. of records (%d) ignored\n", ...
+                      nrec);
+              s_recs (find (srecs > nrec)) = [];
+            endif
+          catch
+            error ("shaperead: numeric value or array expected for RecordNumbers\n");
+          end_try_catch
+        case "sel"
+          ## A hard one, to be implemented later?
+          printf ("shaperead: 'Selector' option not implemented, option ignored\n");
+        case "use"
+          ## Return a geostruct or a mapstruct (default). Only for ML-structs
+          if (outopts != 0)
+            error ("shaperead: UseGeoCoords only valid for Matlab-style output\n");
           endif
-        catch
-          error ("shaperead: numeric value or array expected for RecordNumbers\n");
-        end_try_catch
-      case "sel"
-        ## A hard one, to be implemented later?
-        printf ("shaperead: 'Selector' option not implemented, option ignored\n");
-      case "use"
-        ## Return a geostruct or a mapstruct (default). Only for ML-structs
-        if (outopts != 0)
-          error ("shaperead: UseGeoCoords only valid for Matlab-style output\n");
-        endif
-        try
-          s_geo = logical (varargin{ii+1});
-        catch
-          error ("shaperead: logical value type expected for 'UseGeoCoords'\n");
-        end_try_catch
-      otherwise
-        warning ("shaperead: unknown option '%s' - ignored\n", varargin{ii});
-    endswitch
+          try
+            s_geo = logical (varargin{ii+1});
+          catch
+            error ("shaperead: logical value type expected for 'UseGeoCoords'\n");
+          end_try_catch
+        otherwise
+          warning ("shaperead: unknown option '%s' - ignored\n", varargin{ii});
+      endswitch
+    endif
   endfor
   ## Post-processing
   if (clip)
@@ -358,10 +353,10 @@ function [ outs, oatt ] = shaperead (fname, varargin);
       warning ("shaperead: no BoundingBox supplied => Clip option ignored.\n");
       clip = 0;
     endif
-    if (isempty (which ("oc_polybool")))
-      ## No OF octclip package?
-      printf  ("shaperead: function 'oc_polybool' not found. Clip option ignored\n");
-      warning ("           (OF octclip package installed and loaded?)\n");
+    if (isempty (which ("clipPolygon_clipper")))
+      ## No OF geometry package?
+      printf  ("shaperead: function 'clipPolygon' not found. Clip option ignored\n");
+      warning ("           (OF geometry package installed and loaded?)\n");
       clip = 0;
     endif
     if (isempty (which ("distancePoints")))
@@ -372,14 +367,21 @@ function [ outs, oatt ] = shaperead (fname, varargin);
     endif
   endif
 
+  if (fidp < 0)
+    ## Only now convey file open error message
+    error ("shaperead: can't open file %s\n", fname);
+  else
+    ## Open .shp file
+    fidp = fopen (fname, "r");
+  endif
+  if (fidx < 0)
+    warning ("shaperead: index file %s not found\n", [fnm ".shx"]);
+  endif
+
   ## ============= Preparations done, now we can start reading ============
   ## ---------------------- 2. Read .shp file proper ----------------------
 
   ## Start reading header
-  fidp = fopen (fname, 'r');
-  if (fidp < 0)
-    error ("shaperead: couldn't open file %s\n", fname);
-  endif
   fseek (fidp, 0, "bof");
 
   ## Read & check file code
@@ -405,12 +407,13 @@ function [ outs, oatt ] = shaperead (fname, varargin);
   ##        it. Initial tries showed no significant speed advantage yet over
   ##        the incremental allocation scheme implemented in Ls. 611+ & 631+
   ##        for oct/plt style output. For ml-style it is much harder as
-  ##        we'd need to preallocate a potentially very heterogeneous strtuct
+  ##        we'd need to preallocate a potentially very heterogeneous struct
   ##        array.
 
   ## Prepare for unsupported (in ML output) shape types
   unsupp = 0;
-  ign_mz = (outopts == 0);
+  ## Echo warning if dbug was set
+  ign_mz = (outopts == 0) && dbug;
   ## Buffer for record data
   BUFSIZE = 10000;
   ## Read records, 1 by 1. Initialize final array
@@ -419,7 +422,7 @@ function [ outs, oatt ] = shaperead (fname, varargin);
   nshp = 0;
   ## Temp pointer to keep track of array size and increase it w. BUFSIZE rows
   ivals = 1;
-  ## Assume file has M (measure) values
+  ## Provisionally assume file has M (measure) values
   has_M = true;
 
   ## Record index number (equals struct element number)
@@ -469,40 +472,50 @@ function [ outs, oatt ] = shaperead (fname, varargin);
 
         case 8                                              ## Multipoint
           ## Read bounding box
-          tbbox            = fread (fidp, 4, "double");
+          tbbox(1:4)       = fread (fidp, 4, "double");
           tnpt             = fread (fidp, 1, "int32");
-          val              = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
+          val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
           val(1:tnpt, 3:4) = NaN;
           ## Copy rec index & type down
-          val(2:tnpt, 5:6) = val(1, 5:6);
+          val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
           tnpr             = 0;
 
         case 18                                             ## MultipointZ
-          tbbox            = fread (fidp, 4, "double");
+          tbbox(1:4)       = fread (fidp, 4, "double");
           tnpt             = fread (fidp, 1, "int32");
           val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
           ## Z min & max values
           tbbox(5:6)       = fread (fidp, 2, "double");
           ## Augment val array with Z values
-          val(1:tnpt, 3)   = [ rec(ir).points fread(fidp, tnpt, "double")' ];
+          val(1:tnpt, 3)   = fread(fidp, tnpt, "double")';
           ## M min & max values
           tbbox(7:8)       = fread (fidp, 2, "double");
-          ## Augment val array with M values
-          val(1:tnpt, 4)   = [ rec(ir).points fread(fidp, tnpt, "double")' ];
-          ## Copy rec index & type down
-          val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
-          tnpr             = 0;
+          if (val(1, 5) == 1)
+            has_M = checkM (fidp, val(1, 6), shpbox);
+          endif
+          if (has_M)
+            ## Augment val array with M values
+            val(1:tnpt, 4) = fread(fidp, tnpt, "double")';
+            ## Copy rec index & type down
+            val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
+            tnpr           = 0;
+          endif
 
         case 28                                             ## MultipointM
           tbbox(1:4)       = fread (fidp, 4, "double");
           tnpt             = fread (fidp, 1, "int32");
           val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
           ## Insert empty column for Z
-          val(1:tnpt, 4)   = NaN;
-          ## M min & max values
-          bbox(7:8)        = fread (fidp, 2, "double");
-          ## Augment val array with Z values
-          val(1:tnpt, 4)   = [ rec(ir).points fread(fidp, tnpt, "double")' ];
+          val(1:tnpt, 3:4) = NaN;
+          if (val(1, 5) == 1)
+            has_M = checkM (fidp, val(1, 6), shpbox);
+          endif
+          if (has_M)
+            ## M min & max values
+            tbbox(7:8)     = fread (fidp, 2, "double");
+            ## Augment val array with M values
+            val(1:tnpt, 4) = fread(fidp, tnpt, "double")';
+          endif
           ## Copy rec index & type down
           val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
           tnpr             = 0;
@@ -531,11 +544,16 @@ function [ outs, oatt ] = shaperead (fname, varargin);
           ## Z min & max values + data
           tbbox(5:6)       = fread (fidp, 2, "double");
           val(1:tnpt, 3)   = fread(fidp, tnpt, "double")';
-          ## M min & max values + data
-          tbbox(7:8)       = fread (fidp, 2, "double");
-          val(1:tnpt, 4)   = fread(fidp, tnpt, "double")';
-          ## Copy rec index and type down
-          val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
+          if (val(1, 5) == 1)
+            has_M = checkM (fidp, val(1, 6), shpbox);
+          endif
+          if (has_M)
+            ## M min & max values + data
+            tbbox(7:8)       = fread (fidp, 2, "double");
+            val(1:tnpt, 4)   = fread(fidp, tnpt, "double")';
+            ## Copy rec index and type down
+            val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
+          endif
 
         case {23, 25}                                       ## Polyline/-gonM
           tbbox(1:4)       = fread (fidp, 4, "double");
@@ -547,11 +565,16 @@ function [ outs, oatt ] = shaperead (fname, varargin);
           val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
           ## No Z data
           val(1:tnpt, 3)   = NaN;
-          ## M min & max values + data
-          tbbox(7:8)       = fread (fidp, 2, "double");
-          val(1:tnpt, 4)   = fread(fidp, tnpt, "double")';
-          ## Copy rec index and type down
-          val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
+          if (val(1, 5) == 1)
+            has_M = checkM (fidp, val(1, 6), shpbox);
+          endif
+          if (has_M)
+            ## M min & max values + data
+            tbbox(7:8)       = fread (fidp, 2, "double");
+            val(1:tnpt, 4)   = fread(fidp, tnpt, "double")';
+            ## Copy rec index and type down
+            val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
+          endif
 
         case 31                                             ## Multipatch
           tbbox(1:4)       = fread (fidp, 4, "double");
@@ -562,16 +585,7 @@ function [ outs, oatt ] = shaperead (fname, varargin);
           ## Provisionally transpose, this is later on reset after NaN insertion
           tnpr             = reshape (fread (fidp, nparts*2, "int32")', [], 2)';
           ## Read XY point coordinates
-%        val = NaN (tnpt + size (tnpr, 2) - 1, 6);
-%        ipt = 1;
-%        ttnpr = [tnpr(1, :) tnpt];
-%        for ii=2:numel (ttnpr)
-%          val(ipt:ipt+ttnpr(ii)-1, 1:2) = ...
-%              reshape (fread (fidp, ttnpr(ii)*2, "double"), 2, [])';
-%          ipt +=ttnpr(ii) + 1;
-%        endfor  
           val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
-          
           ## Z min & max values + data. Watch out for incomplete .shp file
           EOF = (ftell (fidp) > flngt-2);
           if (! EOF)
@@ -581,19 +595,7 @@ function [ outs, oatt ] = shaperead (fname, varargin);
           fptr = ftell (fidp);
           EOF = (fptr > flngt-2);
           if (! EOF && has_M)
-            ## Check if the file really contains M values: try to read ("peek")
-            ## three int32 record numbers matching the next record nr. to be
-            ## read, the next record length and 31 (= MultiPatch type)
-            tmp = fread (fidp, 2, "int32", 0, "ieee-be");
-            tmp(3) = fread (fidp, 1, "int32");
-            fseek (fidp, fptr, "bof");
-            if (tmp(1) == (val(1, 5) + 1) && tmp(3) == 31)
-              ## Undoubtedly a record index number. 
-              has_M = false;
-              ## Empirically the min/maxM values in file header mean nothing, so
-              shpbox.M(1) = 0;
-              shpbox.M(2) = 0;
-            endif
+            has_M = checkM (fidp, val(1, 6), shpbox);
           endif
           ## M min & max values + data. Watch out for incomplete .shp file
           if (! EOF && has_M)
@@ -615,9 +617,17 @@ function [ outs, oatt ] = shaperead (fname, varargin);
 
       endswitch
 
+      ## Check if (X, Y) are valid coordinates
+      if (any (abs (val(:, 1:2)) > 1.797e308))
+        ## Probably +/- Inf
+        rincl = 0;
+        if (dbug)
+          printf ("shape# %d has no finite XY coordinates, skipped\n", ir);
+        endif
+
       ## Detect if shape lies (partly) within or completely out of BoundingBox.
       ## Null shapes are automatically skipped
-      if (! isempty (s_bbox))
+      elseif (! isempty (s_bbox))
         ## Just check if any shape feature bounding box corner lies in s_bbox
         tbox = [tbbox(1) tbbox(2); tbbox(1) tbbox(4); ...
                 tbbox(3) tbbox(4); tbbox(3) tbbox(2); tbbox(1) tbbox(2)];
@@ -649,14 +659,10 @@ function [ outs, oatt ] = shaperead (fname, varargin);
         if (rincl && clip)
           ## What to do depends on shape type. Null and MultiPatch aren't clipped
           switch val(1, 6)
-            case {3, 13, 33}                                ## Polyline
-              ## Temporarily silence Octave a bit, then call clipplg
+            case {3, 13, 23, 5, 15, 25, 31}                   ## Polyline/gon, Multipatch
+              ## Temporarily silence Octave a bit, then call clippln
               warning ("off",  "Octave:broadcast", "local");
               [val, tnpt, tnpr] = clippln (val, tnpt, tnpr, sbox, val(1, 6));
-            case {5, 15, 25, 31}                            ## Polygon, Multipatch
-              ## Temporarily silence Octave a bit, then call clipplg
-              warning ("off",  "Octave:broadcast", "local");
-              [val, tnpt, tnpr] = clipplg (val, tnpt, tnpr, sbox, val(1, 6));
             otherwise
               warning ("shaperead: unknown shape type found (%d) - ignored\n", ...
                        val(1, 6));
@@ -682,6 +688,10 @@ function [ outs, oatt ] = shaperead (fname, varargin);
         ## Keep track of nr of shape features read
         ++nshp;
 
+        ## M-values < -1e39 really mean absent values
+        im = find (val(:, 4) < -1e39);
+        val(im, 4) = NaN;
+
         if (outopts < 3)
           ## Prepare an Octave or Matlab style struct optimized for fast
           ## plotting by inserting a NaN row after each polyline/-gon part
@@ -700,7 +710,7 @@ function [ outs, oatt ] = shaperead (fname, varargin);
 
         ## Shape either included by default or it lies in requested BoundingBox
         switch outopts
-          case {0, 1, "ml", "e"}
+          case {0, 1}
             ## Return a ML compatible mapstruct. Attributes will be added later
             if (ign_mz && val(1, 6) >= 10)
               printf ("shaperead: M and Z values ignored for ml-style output\n");
@@ -708,55 +718,60 @@ function [ outs, oatt ] = shaperead (fname, varargin);
             endif
             switch val(1, 6)
               case {1, 11, 21}                              ## Point
-                outs(end+1).Geometry = "Point";
+                outs(end+1, 1).Geometry = "Point";
               case {8, 18, 28}                              ## Multipoint
-                outs(end+1).Geometry = "MultiPoint";
+                outs(end+1, 1).Geometry = "MultiPoint";
               case {3, 13, 23}                              ## Polyline
-                outs(end+1).Geometry = "Line";
+                outs(end+1, 1).Geometry = "Line";
               case {5, 15, 25}                              ## Polygon
-                outs(end+1).Geometry = "Polygon";
+                outs(end+1, 1).Geometry = "Polygon";
               otherwise
                 if (outopts == 1)
                   ## "Extended" ML-style output struct
                   if (val(1, 6) == 31)                      ## MultiPatch
-                    outs(end+1).Geometry = "MultiPatch";
-                    outs(end).Parts = tnpr;
+                    outs(end+1, 1).Geometry = "MultiPatch";
+                    outs(end, 1).Parts = tnpr;
                   endif
                 else
                   if (! unsupp)
-                    warning ("shaperead: shapefile contains unsupported shape types\n");
-                    outs = [];
+                    warning ("shaperead: shapefile contains unsupported shape \
+types\n");
+                    outs = oatt = [];
                     return
                   endif
-                  outs(end+1).Geometry = val(1, 6);
+                  outs(end+1, 1).Geometry = val(1, 6);
                 endif
             endswitch
-            outs(end).BoundingBox = reshape (tbbox(1:4), 2, [])';
+            ## Omit BoundingBox for Point
+            if (all ([1, 11, 21] - val(1, 6)))
+              outs(end).BoundingBox = reshape (tbbox(1:4), 2, [])';
+            endif
             if (s_geo)
-              outs(end).Lon = val(:, 1)';
-              outs(end).Lat = val(:, 2)';
+              outs(end, 1).Lon = val(:, 1)';
+              outs(end, 1).Lat = val(:, 2)';
             else
-              outs(end).X = val(:, 1)';
-              outs(end).Y = val(:, 2)';
+              outs(end, 1).X = val(:, 1)';
+              outs(end, 1).Y = val(:, 2)';
             endif
             ## (ML-incompatible) add Z- and optional M-values, if any
             if (outopts == 1 && any (isfinite (val(:, 4))))
-              outs(end).M = val(:, 4)';
+              outs(end, 1).M = val(:, 4)';
               ## FIXME Decision needed if field Geometry should reflect the type
               ##  outs{end}.Geometry = [ outs{end}.Geometry "M"];
             endif
             if (outopts == 1 && any (isfinite (val(:, 3))))
-              outs(end).Z = val(:, 3)';
+              outs(end, 1).Z = val(:, 3)';
               ## FIXME Decision needed if field Geometry should reflect the type
               ## outs{end}.Geometry = [ outs{end}.Geometry "Z"];
             endif
             ## (ML-incompatible) add Z- and optional M-values, if any
             if (dbug)
               ## Add a field with shape feature identifier for boundingbox
-              outs(end).___Shape_feature_nr___ = val(1, 5);
+              outs(end, 1).___Shape_feature_nr___ = val(1, 5);
             endif
 
-          case {2, "oct"}
+          case {2}
+            ## Return an Octave style struct.
             ## Append to vals array; keep track of appended nr. of rows
             lvals = size (vals, 1);
             lval = size (val, 1);
@@ -779,8 +794,8 @@ function [ outs, oatt ] = shaperead (fname, varargin);
             endif
             bbox = [bbox; tbbox];
 
-          case {3, "dat"}
-            ## Return an Octave style struct. 
+          case {3}
+            ## Return a compressed Octave style struct.
             ## Simply append to vals array; keep track of appended nr. of rows
             lvals = size (vals, 1);
             lval = size (val, 1);
@@ -815,12 +830,13 @@ function [ outs, oatt ] = shaperead (fname, varargin);
     
   until (ftell (fidp) > flngt - 3 ||
          (have_shx && ir > numel (s_recs)));                ## i.e., within last
-                                                            ## file bytes or 
+                                                            ## file bytes or all
+                                                            ## req. records read
   fclose (fidp);
 
   ## If no shape was read, or none fitted within BoundingBox, return empty
   if (nshp < 1)
-    outs = {};
+    outs = oatt = {};
     return;
   endif
   
@@ -875,11 +891,16 @@ function [ outs, oatt ] = shaperead (fname, varargin);
   endif
 
   ## ---------------------- 3. .dbf ----------------------
-  
+
+  if (iscell (s_atts) && isempty (s_atts))
+    ## {} indicates no attributes to be read. Morph into ""
+    return;
+  endif
   ## Check if dbfread is available
   if (isempty (which ("dbfread")))
     printf ("shaperead.m: dbfread function not found. No attributes will be added.\n");
     printf ("             (io package installed and loaded?)\n");
+    oatt = {};
 
   else
     ## Try to read the .dbf file
@@ -887,8 +908,7 @@ function [ outs, oatt ] = shaperead (fname, varargin);
       atts = dbfread ([ bname ".dbf" ], s_recs, s_atts);
       if (outopts < 2)
         ## First check if any attributes match fieldnames; if so, pre-/append "_"
-        tags = {"shpbox", "vals", "bbox", "npt", "npr", "idx", "Geometry", ... 
-                "BoundingBox", "X", "Y", "Lat", "Lon"};
+        tags = {"Geometry", "BoundingBox", "X", "Y", "Lat", "Lon"};
         for ii=1:numel (tags)
           idx = find (strcmp (tags{ii}, atts(1, :)));
           if (! isempty (idx))
@@ -908,9 +928,13 @@ function [ outs, oatt ] = shaperead (fname, varargin);
           for ii=1:size (atts, 2)
             [oatt.(atts{1, ii})] = deal (atts(2:end, ii){:});
           endfor
+          oatt = oatt';
         endif
       else
         ## Octave output struct. Add attributes columns as struct fields
+        ## Check if any attributes match fieldnames; if so, pre-/append "_"
+        tags = {"shpbox", "vals", "bbox", "npt", "npr", "idx", "Geometry", ... 
+                "BoundingBox", "X", "Y", "Lat", "Lon"};
         for ii=1:size (atts, 2)
           outs.fields(end+1) = atts{1, ii};
           if (islogical (atts{2, ii}) || isnumeric (atts{2, ii}))
@@ -928,3 +952,31 @@ function [ outs, oatt ] = shaperead (fname, varargin);
   endif
 
 endfunction
+
+
+function has_M = checkM (fidp, ft, shpbox)
+
+  has_M = true;
+  ## Check if we do have M-values. If so, the next 3 4-byte words 
+  ## comprise the next record nr, rec length and shape type
+  fptr   = ftell (fidp);
+  tmp    = fread (fidp, 2, "int32", 0, "ieee-be");
+  tmp(3) = fread (fidp, 1, "int32");
+  if (tmp(1) == 2 && tmp(3) == ft)
+    ## Looks like next record header + next shape feature type => no M
+    has_M = false;
+    shpbox.M(1) = 0;
+    shpbox.M(2) = 0;
+  endif
+  fseek (fidp, fptr, "bof");
+
+endfunction
+
+
+## Only check input validation. I/O is tested in shapewrite.m
+%!error <arg. #2 char value should be one of> shaperead ('tst.shp', 'j');
+%!error <shaperead: arg. #2 integer value out of range> shaperead ('tst.shp', 7);
+%!error <illegal value for arg. #2:> shaperead ('tst.shp', 'deb')
+%!error < property name expected> shaperead ('tst.shp', "ml", []);
+%!error <numeric or logical value expected> shaperead ('tst.shp', 'deb', {});
+
diff --git a/inst/shapewrite.m b/inst/shapewrite.m
index 7e85e24..325c646 100644
--- a/inst/shapewrite.m
+++ b/inst/shapewrite.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014,2015 Philip Nienhuis
+## Copyright (C) 2014-2020 Philip Nienhuis
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
@@ -15,38 +15,56 @@
 
 ## -*- texinfo -*- 
 ## @deftypefn {Function File} {@var{status} =} shapewrite (@var{shpstr}, @var{fname})
+## @deftypefnx {Function File} {@var{status} =} shapewrite (@var{shpstr}, @var{fname}, @var{atts})
 ## Write contents of map- or geostruct to a GIS shape file.
 ##
 ## @var{shpstr} must be a valid mapstruct or geostruct, a struct array with an
 ## entry for each shape feature, with fields Geometry, BoundingBox, and X and Y
 ## (mapstruct) or Lat and Lon (geostruct).  For geostructs, Lat and Lon field
 ## data will be written as X and Y data.  Field Geometry can have data values
-## of "Point", "MultiPoint", "Line", or "Polygon", all case-insensitive.  For
-## each shape feature, field BoundingBox should contain the minimum and maximum
-## (X,Y) coordinates in a 2x2 array [minX, minY; maxX, maxY].  The X and Y
-## fields should contain X (or Latitude) and Y (or Longitude) coordinates for
-## each point or vertex as row vectors; for polylines and polygons vertices of
-## each subfeature (if present) should be separated by NaN entries.
+## of "Point", "MultiPoint", "Line" or "Polygon", all case-insensitive.
+## For each shape feature, field BoundingBox should contain the minimum and
+## maximum (X,Y) coordinates in a 2x2 array [minX, minY; maxX, maxY].
+## The X and Y fields should contain X (or Latitude) and Y (or Longitude)
+## coordinates for each point or vertex as row vectors; for
+## poly(lines) and polygons vertices of each subfeature (if present) should be
+## separated by NaN entries.
+##
+## <Geometry>M or <Geometry>Z types (e.g., PointM, PolygonZ) can also be
+## written; shapewrite.m just checks if fields "M" and/or "Z" are present in
+## input mapstruct.
 ##
 ## @var{fname} should be a valid shape file name, optionally with a '.shp'
 ## suffix.
 ##
-## shapewrite produces 2 or 3 files, i.e. a .shp file (the actual shape file),
-## a .shx file (index file), and if @var{shpstr} contained additional fields,
-## a .dbf file (dBase type 3) with the contents of those additional fields.
+## Optional third input argument @var{atts} is one attribute name or a cellstr
+## array containing a list of attribute names; only those attributes will be
+## written to the .dbf file.  Alternatively a struct can be supplied with
+## attibute names contained in field "FieldName" (preferrably camelcased as
+## shown, but Octave treats this field's name as case-insensitive).  If
+## argument @var{atts} is omitted all attributes will be written to the
+## shapefile.
+##
+## shapewrite produces 3 files, i.e. a .shp file (the actual shape file),
+## a .shx file (index file), and a .dbf file (dBase type 3) with the contents
+## of additional attribute fields other than Geometry, X/Y or Lat/Lon, M, Z,
+## and BoundingBox.  If no additional attributes are present, a .dbf file is
+## created with the shape feature numbers as contents of field "ID".
+##
+## Return argument @var{status} is set to 1 if the complete shape file set was
+## written successfully, to 0 otherwise.
 ##
-## @var{status} is 1 if the shape file set was written successfully, 0
-## otherwise.
+## Ref: http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf
 ##
 ## @seealso{shapedraw, shapeinfo, shaperead}
 ## @end deftypefn
 
 ## Author: Philip Nienhuis <prnienhuis@users.sf.net>
 ## Created: 2014-12-30
-## 2015-06-26 Three fixes by Jan Heckman
 
-function [status] = shapewrite (shp, fname, atts=[])
+function [status] = shapewrite (shp, fname="", atts=[])
 
+  persistent n_dbfspec = 0;
   status = 0;
 
   ## Input validation
@@ -56,7 +74,7 @@ function [status] = shapewrite (shp, fname, atts=[])
 
   ## Assess shape variable type (oct or ml/geo ml/map)
   if (! isstruct (shp))
-    error ("shapewrite: [map-, geo-] struct expected for argument #2");
+    error ("shapewrite: [map-, geo-] struct expected for argument #1");
   else
     ## Yep. Find out what type
     fldn = fieldnames (shp);
@@ -75,36 +93,97 @@ function [status] = shapewrite (shp, fname, atts=[])
       ## Not a supported struct type
       error ("shapewrite: unsupported struct type.\n")
     endif
-    if (any (ismember ({"M", "Z"}, fldn)))
-      otype = -otype;
-    endif
+  endif
+
+  ## FIXME struct field type validation
+
+  if (strcmpi (shp(1).Geometry, "MultiPatch"))
+    error ("shapewrite.m: MultiPatch type not supported");
+  endif
+
+  ## Check for dbfwrite function
+  if (isempty (which ("dbfwrite")))
+    error ("shapewrite.m: dbfwrite function not found. (io package installed \
+and loaded?)");
+    return;
   endif
 
   ## Check file name
-  [pth, fnm, ext] = fileparts (fname);
-  if (isempty (ext))
-    bname = fname;
-    fname = [fname ".shp"];
+  if (isempty (fname))
+    error ("shapewrite: filename expected for input argument #2");
   else
-    ## Later on bname.shx and bname.dbf will be read
-    bname = [pth fnm];
+    [pth, fnm, ext] = fileparts (fname);
+    if (isempty (ext))
+      bname = fname;
+      fname = [fname ".shp"];
+    ## Later on bname.shx and bname.dbf will be created
+    elseif (isempty (pth))
+      bname = fnm;
+    else
+      bname = [pth filesep fnm];
+    endif
+  endif
+
+  ## Check optional 3rd argument
+  if (nargin > 2)
+    if (isstruct (atts))
+      if (! n_dbfspec)
+        warning ("shapewrite.m: DbfSpec not implemented; including requested \
+attributes\n");
+        n_dbfspec = 1;
+      endif
+      ## Get attribute names from field "FieldName"; allow lowercase and camelcase
+      ## Index of case-insensitive matches of "FieldName"
+      fnidx = find (ismember ("fieldname", lower (fieldnames (atts))));
+      if (! isempty (fnidx))
+        ## Get fieldnames out of first match
+        atts = {atts.(fieldnames (atts (fnidx)){1})};
+      else
+        warning ("shapewrite.m: no field 'fieldname' (case-insensitive) found \
+in struct\n=> input arg. #3 ignored");
+      endif
+    elseif (! iscellstr (atts) && ! ischar (atts))
+      error ("shapewrite.m: arg.#3: attribute name or cellstr array of attribute names expected");
+    endif
+    ## Check if requested attributes exist at all in shapestruct
+    atts = unique (atts);
+    mtch = ! ismember (atts, fieldnames (shp));
+    if (any (mtch))
+      warning ("shapewrite.m: requested attribute(s) '%s' not in shapestruct\n", ...
+               strjoin (atts(find (mtch)), "', '"));
+      atts(mtch) = [];
+    endif
   endif
 
   ## Prepare a few things
   numfeat = numel (shp);
   if (abs (otype) >= 1)
-    stype = find (strcmpi (shp(1).Geometry, ...
-                  {"Point", "MultiPoint", "Line", "Polygon"}));
-    stype = [1, 8, 3, 5](stype);
+    stype = strmatch (lower (shp(1).Geometry), ...
+                  {"point", "multipoint", "line", "polygon"});
+    if (isempty (stype))
+      ## Not a supported struct type
+      error ("shapewrite: unsupported struct type.\n")
+    else
+      stype = [1, 8, 3, 5](stype);
+    endif
+
+    ## Preprocess geostructs
     if (abs (otype) == 2)
       ## Change Lat/Lon fields into X/Y
       [shp.X] = deal (shp.Lon);
       [shp.Y] = deal (shp.Lat);
-%%    shp = rmfield (shp, {"Lat", "Lon"});
     endif
     ## "Point" need not have a BoundingBox field => add a dummy if not found
     if (stype == 1 && ! ismember ("BoundingBox", fldn))
-      [shp.BoundingBox] = deal (repmat (zeros (0, 0), numel (shp)));
+      [shp.BoundingBox] = deal ([0, 0; 0, 0]);
+    endif
+    if (any (ismember ({"M", "Z"}, fldn)))
+      if (ismember ({"Z"}, fldn))
+        stype += 10;
+      else
+        stype += 20;
+      endif
+      otype = -otype;
     endif
   endif
 
@@ -116,14 +195,16 @@ function [status] = shapewrite (shp, fname, atts=[])
   fseek (fids, 0, "bof");
   fidx = fopen ([ bname ".shx" ], "w");
   if (fidx < 0)
-    error ("shapewrite: indexfile %s can't be opened for writing\n", fname);
+    error ("shapewrite: index file %s can't be opened for writing\n", fname);
   endif
   fseek (fidx, 0, "bof");
 
-  ## Write headers in .shp & .shx (identical). First magic number 9994 + 5 zeros
+  ## Write headers in .shp & .shx (identical). First magic number 9994 + six
+  ## zeros, the last zero in .shp is a placeholder for the yet unknown .shp
+  ## file length.
   fwrite (fids, [9994 0 0 0 0 0 0], "int32", 0, "ieee-be");
   fwrite (fidx, [9994 0 0 0 0 0],   "int32", 0, "ieee-be");
-  ## In between here = filelength in 16-bit words (single). For .shx it's known
+  ## For .shx the file length in 16-bit words (single) is known:
   fwrite (fidx, ((numfeat * 4) + 50), "int32", 0, "ieee-be");
   ## Next, shp file version
   fwrite (fids, 1000, "int32");
@@ -135,8 +216,8 @@ function [status] = shapewrite (shp, fname, atts=[])
   fwrite (fids, [0 0 0 0 0 0 0 0], "double");
   fwrite (fidx, [0 0 0 0 0 0 0 0], "double");
   ## Prepare BoundingBox limits
-  xMin = yMin = Inf; 
-  xMax = yMax = -Inf;
+  xMin = yMin = zMin = mMin =  Inf; 
+  xMax = yMax = zMax = mMax = -Inf;
 
   ## Skip to start of first record position
 %  fseek (fids, 100, "bof");
@@ -148,74 +229,226 @@ function [status] = shapewrite (shp, fname, atts=[])
       ## Write record start pos to .shx file
       fwrite (fidx, ftell (fids) / 2, "int32", 0, "ieee-be");
 
+      ## Prepare multipart polygons/lines.
+      ## Find pointers to separators
+      idx = [ 0 find(isnan (shp(ishp).X)) ];
+      ## Eliminate trailing NaN rows
+      if (isnan (shp(ishp).X))
+        idx(end) = [];
+      endif
+      ## Augment idx for later on
+      idx = unique ([ idx (numel (shp(ishp).X)+1) ]);
+      ## Remove NaN separators
+      idn = find (! isfinite (shp(ishp).X));
+      shp(ishp).X(idn) = [];
+      shp(ishp).Y(idn) = [];
+      if (stype >= 10)
+        shp(ishp).Z(idn) = [];
+      endif
+      if (stype >= 10)
+        shp(ishp).M(idn) = [];
+        ## M as need not be present (we assume a NaN value then).
+        ## Set M to a value less than -1e39
+        idm = find (! isfinite (shp(ishp).M));
+        shp(ishp).M(idm) = -1.1e39;
+      endif
+      ## Nr. of vertices
+      npt = numel (shp(ishp).X);
+      ## Pointers to parts
+      nptr = idx(1:end-1) .- [0:numel(idx)-2];
+
       ## Write record contents
       switch (stype)
         case 1                                                ## Point
-          ## Record index number
-          fwrite (fids, ishp, "int32", 0, "ieee-be");
-          ## Record length (fixed)
-          reclen = 20;
-          fwrite (fids, reclen, "int32", 0, "ieee-be");
+          reclen = 10;
+          ## Write record index number & content length (fixed)
+          fwrite (fids, [ishp reclen], "int32", 0, "ieee-be");
           fwrite (fidx, reclen, "int32", 0, "ieee-be");
-          ## Shape type
+          ## Write shape type
           fwrite (fids, stype, "int32");
           ## Simply write XY cordinates
           fwrite (fids, [shp(ishp).X shp(ishp).Y], "double");
           ## Update overall BoundingBox
-          xMin = min (xMin, shp(ishp).BoundingBox(1, 1));
-          xMax = max (xMax, shp(ishp).BoundingBox(1, 2));
-          yMin = min (yMin, shp(ishp).BoundingBox(2, 1));
-          yMax = max (yMax, shp(ishp).BoundingBox(2, 2));
-          
+          xMin = min (xMin, shp(ishp).X);
+          xMax = max (xMax, shp(ishp).X);
+          yMin = min (yMin, shp(ishp).Y);
+          yMax = max (yMax, shp(ishp).Y);
+
+        case 11                                               ## PointZ
+          reclen = 18;
+          ## Write record index number & content length (fixed)
+          fwrite (fids, [ishp reclen], "int32", 0, "ieee-be");
+          fwrite (fidx, reclen, "int32", 0, "ieee-be");
+          ## Write shape type
+          fwrite (fids, stype, "int32");
+          ## Simply write XY coordinates & Z & M value
+          fwrite (fids, [shp(ishp).X shp(ishp).Y shp(ishp).Z shp(ishp).M], "double");
+          ## Update overall BoundingBox
+          xMin = min (xMin, shp(ishp).X);
+          xMax = max (xMax, shp(ishp).X);
+          yMin = min (yMin, shp(ishp).Y);
+          yMax = max (yMax, shp(ishp).Y);
+          zMin = min (zMin, shp(ishp).Z);
+          zMax = max (zMax, shp(ishp).Z);
+          mMin = min (mMin, shp(ishp).M);
+          mMax = max (mMax, shp(ishp).M);
+
+        case 21                                               ## PointM
+          reclen = 14;
+          ## Write record index number & content length (fixed)
+          fwrite (fids, [ishp reclen], "int32", 0, "ieee-be");
+          fwrite (fidx, reclen, "int32", 0, "ieee-be");
+          ## Write shape type
+          fwrite (fids, stype, "int32");
+          ## Simply write XY coordinates & M-value
+          fwrite (fids, [shp(ishp).X shp(ishp).Y shp(ishp).M], "double");
+          ## Update overall BoundingBox
+          xMin = min (xMin, shp(ishp).X);
+          xMax = max (xMax, shp(ishp).X);
+          yMin = min (yMin, shp(ishp).Y);
+          yMax = max (yMax, shp(ishp).Y);
+          mMin = min (mMin, shp(ishp).M);
+          mMax = max (mMax, shp(ishp).M);
+
         case 8                                                ## MultiPoint
-          ## Record index number
-          fwrite (fids, ishp, "int32", 0, "ieee-be");
-          ## Record length
-          reclen = (48 + 16 * numel (shp(ishp).X)) / 2;
-          fwrite (fids, reclen, "int32", 0, "ieee-be");
+          reclen = (40 + 16 * numel (shp(ishp).X)) / 2;
+          ## Write record index number & content length (fixed)
+          fwrite (fids, [ishp reclen], "int32", 0, "ieee-be");
           fwrite (fidx, reclen, "int32", 0, "ieee-be");
-          ## Shape type
+          ## Write shape type (+4)
           fwrite (fids, stype, "int32");
-          ## Bounding box
+          ## Write bounding box (+32 -> 36)
           fwrite (fids, [shp(ishp).BoundingBox'(:)]', "double");
-          xMin = min (xMin, shp(ishp).BoundingBox(1, 1));
-          xMax = max (xMax, shp(ishp).BoundingBox(1, 2));
-          yMin = min (yMin, shp(ishp).BoundingBox(2, 1));
-          yMax = max (yMax, shp(ishp).BoundingBox(2, 2));
-          ## Nr of points
+          ## Update overall BoundingBox
+          xMin = min (xMin, min (shp(ishp).X));
+          xMax = max (xMax, max (shp(ishp).X));
+          yMin = min (yMin, min (shp(ishp).Y));
+          yMax = max (yMax, max (shp(ishp).Y));
+          ## Write nr of points and XY data (+4 -> 40 + Nx16)
           fwrite (fids, numel (shp(ishp).X), "int32");
-          fwrite (fids, [shp(ishp).X shp(ishp).Y]', "double");
-          reclen = (44 + 16 * numel (shp(ishp).X)) / 2;
-          
+          fwrite (fids, [shp(ishp).X' shp(ishp).Y']', "double");
+
+        case 18                                               ## MultiPointZ
+          reclen = (72 + 32 * numel (shp(ishp).X)) / 2;
+          ## Write record index number & content length (fixed)
+          fwrite (fids, [ishp reclen], "int32", 0, "ieee-be");
+          fwrite (fidx, reclen, "int32", 0, "ieee-be");
+          ## Write shape type
+          fwrite (fids, stype, "int32");
+          ## Write bounding box
+          fwrite (fids, [shp(ishp).BoundingBox'(:)]', "double");
+          ## Update overall BoundingBox
+          xMin = min (xMin, min (shp(ishp).X));
+          xMax = max (xMax, max (shp(ishp).X));
+          yMin = min (yMin, min (shp(ishp).Y));
+          yMax = max (yMax, max (shp(ishp).Y));
+          zMin = min (zMin, min (shp(ishp).Z));
+          zMax = max (zMax, max (shp(ishp).Z));
+          mMin = min (mMin, min (shp(ishp).M));
+          mMax = max (mMax, max (shp(ishp).M));
+          ## Write Nr of points and XY data
+          fwrite (fids, numel (shp(ishp).X), "int32");
+          fwrite (fids, [shp(ishp).X' shp(ishp).Y']', "double");
+          ## Write Z/M range and -data in turn
+          fwrite (fids, [min(shp(ishp).Z) max(shp(ishp).Z) shp(ishp).Z], "double");
+          fwrite (fids, [min(shp(ishp).M) max(shp(ishp).M) shp(ishp).M], "double");
+
+        case 28                                               ## MultiPointM
+          reclen = (56 + 24 * numel (shp(ishp).X)) / 2;
+          ## Write record index number & content length (fixed)
+          fwrite (fids, [ishp reclen], "int32", 0, "ieee-be");
+          fwrite (fidx, reclen, "int32", 0, "ieee-be");
+          ## Write shape type
+          fwrite (fids, stype, "int32");
+          ## Write bounding box
+          fwrite (fids, [shp(ishp).BoundingBox'(:)]', "double");
+          ## Update overall BoundingBox
+          xMin = min (xMin, min (shp(ishp).X));
+          xMax = max (xMax, max (shp(ishp).X));
+          yMin = min (yMin, min (shp(ishp).Y));
+          yMax = max (yMax, max (shp(ishp).Y));
+          mMin = min (mMin, min (shp(ishp).M));
+          mMax = max (mMax, max (shp(ishp).M));
+          ## Write Nr of points and XY data
+          fwrite (fids, numel (shp(ishp).X), "int32");
+          fwrite (fids, [shp(ishp).X' shp(ishp).Y']', "double");
+          ## Write M range and M data
+          fwrite (fids, [min(shp(ishp).M) max(shp(ishp).M) shp(ishp).M], "double");
+
         case {3, 5}                                           ## Polyline/-gon
-          ## Record index number
-          fwrite (fids, ishp, "int32", 0, "ieee-be");
-          ## Prepare multipart polygons
-          idx = [ 0 find(isnan (shp(ishp).X)) ];
-          npt = numel (shp(ishp).X) - numel (idx) + 1;
-          ## Augment idx for later on, & this trick eliminates trailing NaN rows
-          idx = unique ([ idx npt ]);
-          ## Record length
+          ## Content length
           reclen = (44 + (numel(idx)-1)*4 + 2*8*npt) / 2;
-          fwrite (fids, reclen, "int32", 0, "ieee-be");
+          ## Write record index number & content length (fixed)
+          fwrite (fids, [ishp reclen], "int32", 0, "ieee-be");
+          fwrite (fidx, reclen, "int32", 0, "ieee-be");
+          ## Write shape type
+          fwrite (fids, stype, "int32");
+          ## Write bounding box
+          fwrite (fids, [shp(ishp).BoundingBox'(:)]', "double");
+          ## Update overall BoundingBox
+          xMin = min (xMin, min (shp(ishp).X));
+          xMax = max (xMax, max (shp(ishp).X));
+          yMin = min (yMin, min (shp(ishp).Y));
+          yMax = max (yMax, max (shp(ishp).Y));
+          ## Write number of parts, number of points, part pointers
+          fwrite (fids, [(numel(idx)-1) npt nptr ], "int32");
+          fwrite (fids, [shp(ishp).X' shp(ishp).Y']'(:), "double");
+
+        case {13, 15}                                         ## Polyline/-gonZ
+          ## Content length
+          reclen = (76 + (numel(idx)-1)*4 + 4*8*npt) / 2;
+          ## Write record index number & content length (fixed)
+          fwrite (fids, [ishp reclen], "int32", 0, "ieee-be");
           fwrite (fidx, reclen, "int32", 0, "ieee-be");
           ## Shape type
           fwrite (fids, stype, "int32");
-          ## Bounding box
+          ## Write bounding box
+          fwrite (fids, [shp(ishp).BoundingBox'(:)]', "double");
+          ## Update overall BoundingBox
+          xMin = min (xMin, min (shp(ishp).X));
+          xMax = max (xMax, max (shp(ishp).X));
+          yMin = min (yMin, min (shp(ishp).Y));
+          yMax = max (yMax, max (shp(ishp).Y));
+          zMin = min (zMin, min (shp(ishp).Z));
+          zMax = max (zMax, max (shp(ishp).Z));
+          mMin = min (mMin, min (shp(ishp).M));
+          mMax = max (mMax, max (shp(ishp).M));
+          ## Write number of parts, number of points, part pointers
+          fwrite (fids, [(numel(idx)-1) npt nptr ], "int32");
+          ## Write XY data
+          fwrite (fids, [shp(ishp).X' shp(ishp).Y']'(:), "double");
+          fwrite (fids, [min(shp(ishp).Z) max(shp(ishp).Z) ...
+                         shp(ishp).Z], "double");
+          fwrite (fids, [min(shp(ishp).M) max(shp(ishp).M) ...
+                         shp(ishp).M], "double");
+
+        case {23, 25}                                         ## Polyline/-gonM
+          ## Content length
+          reclen = (60 + (numel(idx)-1)*4 + 3*8*npt) / 2;
+          ## Write record index number & content length (fixed)
+          fwrite (fids, [ishp reclen], "int32", 0, "ieee-be");
+          fwrite (fidx, reclen, "int32", 0, "ieee-be");
+          ## Write shape type
+          fwrite (fids, stype, "int32");
+          ## Write bounding box
           fwrite (fids, [shp(ishp).BoundingBox'(:)]', "double");
-          xMin = min (xMin, shp(ishp).BoundingBox(1, 1));
-          xMax = max (xMax, shp(ishp).BoundingBox(1, 2));
-          yMin = min (yMin, shp(ishp).BoundingBox(2, 1));
-          yMax = max (yMax, shp(ishp).BoundingBox(2, 2));
-          ## Number of parts, number of points, part pointers
-          fwrite (fids, [(numel(idx)-1) npt idx(1:end-1) ], "int32");
-          for ii=1:numel(idx)-1
-            fwrite (fids, [shp(ishp).X(idx(ii)+1:idx(ii+1)) ...
-                           shp(ishp).Y(idx(ii)+1:idx(ii+1))](:)', "double");
-          endfor
-          
+          ## Update overall BoundingBox
+          xMin = min (xMin, min (shp(ishp).X));
+          xMax = max (xMax, max (shp(ishp).X));
+          yMin = min (yMin, min (shp(ishp).Y));
+          yMax = max (yMax, max (shp(ishp).Y));
+          mMin = min (mMin, min (shp(ishp).M));
+          mMax = max (mMax, max (shp(ishp).M));
+          ## Write number of parts, number of points, part pointers
+          fwrite (fids, [(numel(idx)-1) npt nptr ], "int32");
+          ## Write XY data
+          fwrite (fids, [shp(ishp).X' shp(ishp).Y']'(:), "double");
+          ## Write M range and M data
+          fwrite (fids, [min(shp(ishp).M) max(shp(ishp).M) ...
+                         shp(ishp).M], "double");
+
         otherwise
-          ## Future shape types or types unsupported yet (M, Z, MultiPatch)
+          ## Future shape types or types unsupported yet (MultiPatch)
 
       endswitch
     endfor
@@ -227,44 +460,173 @@ function [status] = shapewrite (shp, fname, atts=[])
   fwrite (fids, flen/2, "int32", 0, "ieee-be");
   fseek (fids, 36, "bof");
   fwrite (fids, [xMin yMin xMax yMax], "double");
+  ## Same for .shx header
+  xlen = ftell (fidx);
+  fseek (fidx, 24, "bof");
+  fwrite (fidx, xlen/2, "int32", 0, "ieee-be");
   fseek (fidx, 36, "bof");
   fwrite (fidx, [xMin yMin xMax yMax], "double");
+  if (stype > 10)
+    ## +-Inf & NaN not allowed in shapefiles
+    zm = [zMin zMax mMin mMax];
+    zm (! isfinite (zm)) = -1e-39;
+    fwrite (fids, zm, "double");
+    fwrite (fidx, zm, "double");
+  endif
 
   ## Close files
   fclose (fids);
   fclose (fidx);
 
-  ## Check for dbfwrite function
-  if (isempty (which ("dbfwrite")))
-    printf ("shaperead.m: dbfwrite function not found. No attributes written.\n");
-    printf ("             (io package 2.2.6+ installed and loaded?)\n");
-    return;
+  ## Write .dbf file.
+  ## Remove basic attributes
+  if (abs (otype) == 1)
+    ## Attributes + shp data in mapstruct
+    shp = rmfield (shp, {"Geometry", "BoundingBox", "X", "Y"});
+  elseif (abs (otype) == 2)
+    ## Attributes + shp data in geostruct
+    shp = rmfield (shp, {"Geometry", "BoundingBox", "Lat", "Lon", "X", "Y"});
+  endif
+  if (otype < 1)
+    shp = rmfield (shp, {"M"});
+    if (isfield (shp, "Z"))
+      shp = rmfield (shp, {"Z"});
+    endif
   endif
 
   ## Write rest of attributes
   if (nargin == 3)
-    shp = atts;
-  else
-    if (otype == 1)
-      ## Attributes + shp data in mapstruct
-      shp = rmfield (shp, {"Geometry", "BoundingBox", "X", "Y"});
-    elseif (otype == 2)
-      ## Attributes + shp data in geostruct
-      shp = rmfield (shp, {"Geometry", "BoundingBox", "Lat", "Lon", "X", "Y"});
-    endif
+    ## Only write user-specified attribute selection
+    fldn = fieldnames (shp);
+    ## First remove regular attributes (with a value for each vertex)
+    fldn (ismember (fldn, {"Geometry", "BoundingBox", "Lat", "Lon", "X", "Y", "M", "Z"})) = [];
+    ## Next, only retain user-specified attributes
+    shp = rmfield (shp, setdiff (fldn, atts));
   endif
   attribs = cell (numfeat + 1, numel (fieldnames (shp)));
-  attribs(1, :) = fieldnames (shp);
-  attribs(2:end, :) = (squeeze (struct2cell (shp)))';
-
   if (! isempty (attribs))
-    try
-      status = dbfwrite ([ bname ".dbf"], attribs);
-    catch
-      warning ("shapewrite: writing attributes to file %s failed\n", [bname ".dbf"]);
-    end_try_catch
+    attribs(1, :) = fieldnames (shp);
+    attribs(2:end, :) = (squeeze (struct2cell (shp)))';
   else
-    status = 1;
+    ## Substitute ID attribute
+    attribs{1, 1} = "ID";
+    [attribs{2:end}] = deal (num2cell ([1:size(shp, 2)]){:});
   endif
+  try
+    status = dbfwrite ([ bname ".dbf"], attribs);
+    status = 1;
+  catch
+    warning ("shapewrite: writing attributes to file %s failed\n", [bname ".dbf"]);
+  end_try_catch
 
 endfunction
+
+
+## Test various geometries: (1) Point
+%!test
+%! shp.Geometry = "Point";
+%! shp.X = 10;
+%! shp.Y = 20;
+%! shp.Z = 30;
+%! shp.M = -1;
+%! shp.attr_1 = "Attribute1";
+%! shp.attr_Z = "AttributeA";
+%! shp(2).Geometry = "Point";
+%! shp(2).X = 11;
+%! shp(2).Y = 25;
+%! shp(2).Z = 32;
+%! shp(2).M = -2;
+%! shp(2).attr_1 = "Attribute2";
+%! shp(2).attr_Z = "AttributeB";
+%! fname = tempname ();
+%! sts = shapewrite (shp, fname);
+%! assert (sts, 1, eps);
+%! ## Check index file
+%%! fx = fopen ([fname ".shx"], "r");
+%%! fseek (fx, 100, "bof");
+%%! shxinfo = fread (fx, "*int32", 0, "ieee-be");
+%%! assert (shxinfo, int32 ([50; 36; 72; 36]));
+%%! fclose (fx);
+%! ## Check on filesizes, based on Esri shapewrite doc
+%! assert (stat ([fname ".shp"]).size, 188, 1e-10);
+%! assert (stat ([fname ".shx"]).size, 116, 1e-10);
+%! shp2 = shaperead ([fname ".shp"]);
+%! assert (size (shp2), [2 1]);
+%! flds = fieldnames (shp2);
+%! fields = {"Geometry", "X", "Y", "attr_1", "attr_Z"};
+%! ism = ismember (fields, flds);
+%! ## Do we have only those fields?
+%! assert (numel (ism), numel (fields));
+%! ## Do we have only those fields?
+%! assert (sum (ism), numel (ism));
+%! unlink ([fname ".shp"]);
+%! unlink ([fname ".shx"]);
+%! assert ([shp2.X shp2.Y], [10 11 20 25], 1e-10);
+%! assert ({shp2.Geometry}, {"Point", "Point"});
+%! assert ({shp2.attr_1}, {"Attribute1", "Attribute2"});
+
+## Test various geometries: (2) Line & Polygon
+%!test
+%! shp.Geometry = "Line";
+%! shp.BoundingBox = [9 110; 19 120];
+%! shp.X = [10 110 NaN   9 109];
+%! shp.Y = [20 120 NaN  19 119];
+%! shp.Z = [30 130 NaN  29 129];
+%! shp.M = [-1   1 NaN -11  11];
+%! shp.attr_1 = "Attribute1";
+%! shp.attr_Z = "AttributeA";
+%! shp(2).Geometry = "Line";
+%! shp(2).BoundingBox = [11 211; 24 225];
+%! shp(2).X = [11 111 211 NaN  11 110 NaN  12  200];
+%! shp(2).Y = [25 125 225 NaN  24 124 NaN  26  200];
+%! shp(2).Z = [32 132 232 NaN  31 131 NaN  33  200];
+%! shp(2).M = [-2 NaN  -3 NaN -22  22 NaN -33   33];
+%! shp(2).attr_1 = "Attribute2";
+%! shp(2).attr_Z = "AttributeB";
+%! fname = tempname ();
+%! sts = shapewrite (shp, fname);
+%! assert (sts, 1, eps);
+%! ## Check index file
+%%! fx = fopen ([fname ".shx"], "r");
+%%! fseek (fx, 100, "bof");
+%%! shxinfo = fread (fx, "*int32", 0, "ieee-be");
+%%! assert (shxinfo, int32 ([50; 106; 160; 156]));
+%%! fclose (fx);
+%! ## Check on filesizes, based on Esri shapewrite doc
+%! assert (stat ([fname ".shp"]).size, 640, 1e-10);
+%! assert (stat ([fname ".shx"]).size, 116, 1e-10);
+%!
+%! ## Check Matlab-style reading
+%! shp2 = shaperead ([fname ".shp"]);
+%! assert (size (shp2), [2 1]);
+%! flds = fieldnames (shp2);
+%! fields = {"Geometry", "BoundingBox", "X", "Y", "attr_1", "attr_Z"};
+%! ism = ismember (fields, flds);
+%! ## Do we have only those fields?
+%! assert (numel (ism), numel (fields));
+%! ## Do we have only those fields?
+%! assert (sum (ism), numel (ism));
+%! assert ([shp2.BoundingBox], [9 110 11 211; 19 120 24 225], 1e-10);
+%! assert ({shp2.attr_Z}, {"AttributeA", "AttributeB"});
+%!
+%! ## Re-read using M & Z values, read only 2nd feature
+%! shp2 = shaperead ([fname ".shp"], "e", "rec", 2);
+%! assert (size (shp2), [1 1]);
+%! flds = fieldnames (shp2);
+%! fields = {"Geometry", "BoundingBox", "X", "Y", "Z", "M", "attr_1", "attr_Z"};
+%! ism = ismember (fields, flds);
+%! ## Do we have only those fields?
+%! assert (numel (ism), numel (fields));
+%! ## Do we have only those fields?
+%! assert (sum (ism), numel (ism));
+%! ## Check regular numerical values
+%! assert ([shp2.X; shp2.Y; shp2.Z], ...
+%!         [11, 111, 211, NaN, 11, 110, NaN, 12, 200; ...
+%!          25, 125, 225, NaN, 24, 124, NaN, 26, 200; ...
+%!          32, 132, 232, NaN, 31, 131, NaN, 33, 200], 1e-10);
+%! ## Check missing M value
+%! assert (shp2.M, [-2, NaN, -3, NaN, -22, 22, NaN, -33, 33], 1e-10);
+%! assert ({shp2.attr_1, shp2.attr_Z}, {"Attribute2", "AttributeB"});
+%!
+%! unlink ([fname ".shp"]);
+%! unlink ([fname ".shx"]);
diff --git a/inst/sm2deg.m b/inst/sm2deg.m
index 878d0f8..829dc65 100644
--- a/inst/sm2deg.m
+++ b/inst/sm2deg.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Pooja Rao <poojarao12@gmail.com>
+## Copyright (C) 2014-2020 Pooja Rao <poojarao12@gmail.com>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
diff --git a/inst/sm2km.m b/inst/sm2km.m
index 42cbc18..6555536 100644
--- a/inst/sm2km.m
+++ b/inst/sm2km.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
+## Copyright (C) 2014-2020 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/sm2nm.m b/inst/sm2nm.m
index 69bf2e2..ed0db61 100644
--- a/inst/sm2nm.m
+++ b/inst/sm2nm.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
+## Copyright (C) 2014-2020 Eugenio Gianniti <eugenio.gianniti@mail.polimi.it>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/sm2rad.m b/inst/sm2rad.m
index 2c914c2..e30525e 100644
--- a/inst/sm2rad.m
+++ b/inst/sm2rad.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Pooja Rao <poojarao12@gmail.com>
+## Copyright (C) 2014-2020 Pooja Rao <poojarao12@gmail.com>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
diff --git a/inst/toDegrees.m b/inst/toDegrees.m
index e0afbfd..ecc9f06 100644
--- a/inst/toDegrees.m
+++ b/inst/toDegrees.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/toRadians.m b/inst/toRadians.m
index d00bc46..96590d1 100644
--- a/inst/toRadians.m
+++ b/inst/toRadians.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/unitsratio.m b/inst/unitsratio.m
index 34167e1..ac26500 100644
--- a/inst/unitsratio.m
+++ b/inst/unitsratio.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/utmzone.m b/inst/utmzone.m
new file mode 100644
index 0000000..11e22f5
--- /dev/null
+++ b/inst/utmzone.m
@@ -0,0 +1,206 @@
+## Copyright (C) 2019-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSEll. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{zone} =} utmzone (@var{lat} , @var{long})
+## @deftypefnx {Function File} {@var{latlon} =} utmzone (@var{zone})
+## @deftypefnx {Function File} {@var{lat}, @var{long} =} utmzone (@var{zone})
+## Returns the zone given a latitude and longitude, or the latitude and
+## longitude ranges given a zone.
+##
+## Examples:
+##
+## @example
+## utmzone (43, -79)
+## => ans =
+## 17T
+## @end example
+##
+## Can also handle the special zones of Norway
+##
+## @example
+## utmzone (60, 5)
+## => ans =
+## 32V
+## @end example
+##
+## For zones:
+##
+## @example
+## utmzone ("17T")
+## => ans =
+##  40   48
+## -84  -78
+## @end example
+##
+## @example
+## [lat, lon] = utmzone ("17T")
+## =>
+## lat =
+##    40   48
+## lon =
+##   -84  -78
+## @end example
+##
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9756
+
+function [zone, z2] = utmzone (lat, long)
+
+  ## Since there is no I or O, the last 4 are special cases
+  alphabet = ("CDEFGHJKLMNPQRSTUVWXABYZ");
+
+  if (nargin < 2)
+    if (ischar (lat) && numel (lat) > 1)
+      num = sscanf (lat, "%f");
+      if (num < 1)
+        error ("utmzone.m: positive number expecte for zone");
+      endif
+      let = find (alphabet == upper (lat(end)));
+      if (isempty (let))
+        error ("utmzone.m: incorrect or no letter specified");
+      endif
+      switch upper (lat(end))
+        case "A"
+          lat  = [-80 -90];
+          long = [-180 0];
+          zone = [lat; long];
+        case "B"
+          lat  = [-80 -90];
+          long = [0 180];
+          zone = [lat; long];
+        case "Y"
+          lat  = [84 90];
+          long = [-180 0];
+          zone = [lat; long];
+        case "Z"
+          lat  = [84 90];
+          long = [0 180];
+          zone = [lat; long];
+        case "X"
+          lat  = [72 84];
+          switch num
+            case 31
+              long = [0 9];
+            case 33
+              long = [9 21];
+            case 35
+              long = [21 33];
+            case 37
+              long = [33 42];
+            case {32, 34, 36}
+              error ("utmzone.m : zone %2iX does not exist", num);
+            otherwise
+              long = [(num - 1) * 6 - 180, (num * 6 - 180)];
+          endswitch
+          zone = [lat; long];
+        case  "V"
+          lat = [56 64];
+          switch num
+            case 31
+              long = [0 3];
+            case 32
+              long = [3 12];
+            otherwise
+              long = [(num - 1) * 6 - 180, (num * 6 - 180)];
+          endswitch
+          zone = [lat; long];
+        otherwise
+          lat =  [(let - 1) * 8 - 80, (let * 8) - 80 ];
+          long = [(num - 1) * 6 - 180, (num * 6 - 180)];
+          zone = [lat; long];
+      endswitch
+    endif
+    if (nargout ==2)
+      zone = lat;
+      z2 = long;
+    endif
+
+  elseif (isnumeric (lat) && isreal (lat) && isnumeric (long) && isreal (long))
+    lat  = mean (lat);
+    long = mean (long);
+    if (lat <=  -80)
+        if (long < 0)
+          zone = "A";
+        else
+          zone = "B";
+        endif
+    elseif (lat >= 84)
+        if long < 0
+          zone = "Y";
+        else
+          zone = "Z";
+        endif
+    elseif (lat >= 72 && lat < 84)
+        if (long >= 0 && long < 9)
+          zone = "31X";
+        elseif (long >= 9 && long < 21)
+          zone = "33X";
+        elseif (long >= 21 && long < 33)
+          zone = "35X";
+        elseif (long >= 33 && long < 42)
+          zone = "37X";
+        else
+          zone = zone (lat, long);
+        endif
+    elseif (lat >= 56 && lat < 64)
+        if (long >= 0 && long < 3)
+          zone = "31V";
+        elseif (long >= 3 && long < 12)
+          zone = "32V";
+        endif
+    else
+      zone = zone (lat, long);
+    endif
+
+  else
+    error ("utmzone.m: numeric input expected for LAT en LON");
+
+  endif
+
+endfunction
+
+
+function z = zone (lat, long)
+
+  alphabet = ("CDEFGHJKLMNPQRSTUVWX");
+
+  num = floor ((long + 180) / 6) + 1;
+  idx = -80;
+  ind = 0;
+  while (lat > idx)
+    idx = idx + 8;
+    ind = ind + 1;
+  endwhile
+  let = alphabet (ind);
+  z = strcat (num2str (num), let);
+
+endfunction
+
+
+%!test
+%! lat = 43; ## From Wiki
+%! long =  -79;
+%! assert (utmzone (lat, long), "17T")
+%!assert (utmzone ("17T"), [40, 48;-84, -78])
+%!assert (utmzone (60, 5), "32V") ## For Bergen Norway
+%!assert (utmzone ("32V"), [56, 64;3, 12])
+
+%!error <zone> utmzone ("32X")
+%!error <incorrect> utmzone ("31I")
+%!error <incorrect> utmzone ("31O")
diff --git a/inst/validateLengthUnit.m b/inst/validateLengthUnit.m
index 754bed9..7d1c616 100644
--- a/inst/validateLengthUnit.m
+++ b/inst/validateLengthUnit.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2014 Carnë Draug <carandraug@octave.org>
+## Copyright (C) 2014-2020 Carnë Draug <carandraug@octave.org>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
diff --git a/inst/wgs84Ellipsoid.m b/inst/wgs84Ellipsoid.m
new file mode 100644
index 0000000..9235449
--- /dev/null
+++ b/inst/wgs84Ellipsoid.m
@@ -0,0 +1,79 @@
+## Copyright (C) 2018-2020 Philip Nienhuis
+##
+## This program is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSEll. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} wgs84Ellipsoid (@var{unit})
+##
+## Returns the parameters of the wgs84 ellipsoid. Argument @var{unit} is
+## optional and if given, should be one of the units recognized by function
+## validateLengthUnit().
+##
+## Example:
+## @example
+## >> E = wgs84Ellipsoid
+## E =
+##
+##  scalar structure containing the fields:
+##
+##    Code =  7030
+##    Name = World Geodetic System 1984
+##    LengthUnit = meter
+##    SemimajorAxis =  6378137
+##    SemiminorAxis =    6.3568e+06
+##    InverseFlattening =  298.26
+##    Eccentricity =  0.081819
+##    Flattening =  0.0033528
+##    ThirdFlattening =  0.0016792
+##    MeanRadius =    6.3710e+06
+##    SurfaceArea =    5.1007e+14
+##    Volume =    1.0832e+21
+## @end example
+##
+## A unit argument is also accepted:
+## @example
+## >> E = wgs84Ellipsoid ("km")
+## E =
+##
+##  scalar structure containing the fields:
+##
+##    Code =  7030
+##    Name = World Geodetic System 1984
+##    LengthUnit = km
+##    SemimajorAxis =  6378.1
+##    SemiminorAxis =  6356.8
+##    InverseFlattening =  298.26
+##    Eccentricity =  0.081819
+##    Flattening =  0.0033528
+##    ThirdFlattening =  0.0016792
+##    MeanRadius =  6371.0
+##    SurfaceArea =    5.1007e+08
+##    Volume =    1.0832e+12
+## @end example
+## @seealso{referenceEllipsoid, validateLengthUnit}
+## @end deftypefn
+
+## Function supplied by anonymous contributor, see:
+## https://savannah.gnu.org/patch/index.php?9634
+
+function Ell = wgs84Ellipsoid (unit)
+
+  if ! nargin 
+    unit = "meter";
+  end
+  
+  Ell = referenceEllipsoid ("wgs84", unit);
+
+endfunction
diff --git a/inst/wrapTo180.m b/inst/wrapTo180.m
index c54ba95..7b2798e 100644
--- a/inst/wrapTo180.m
+++ b/inst/wrapTo180.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2015 Oscar Monerris Belda
+## Copyright (C) 2015-2020 Oscar Monerris Belda
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/wrapTo2Pi.m b/inst/wrapTo2Pi.m
index 96e5bb2..f6901be 100644
--- a/inst/wrapTo2Pi.m
+++ b/inst/wrapTo2Pi.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2015 Oscar Monerris Belda
+## Copyright (C) 2015-2020 Oscar Monerris Belda
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/inst/wrapTo360.m b/inst/wrapTo360.m
index 0f01e0e..41f2c72 100644
--- a/inst/wrapTo360.m
+++ b/inst/wrapTo360.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2015 Oscar Monerris Belda
+## Copyright (C) 2015-2020 Oscar Monerris Belda
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
@@ -33,7 +33,7 @@
 ##    10   360   360
 ## @end example
 ##
-## @seealso{wrapTo180, wrapToPi, wrapto2Pi}
+## @seealso{wrapTo180, wrapToPi, wrapTo2Pi}
 ## @end deftypefn
 
 function xwrap = wrapTo360(x)
diff --git a/inst/wrapToPi.m b/inst/wrapToPi.m
index 703c727..c1886d8 100644
--- a/inst/wrapToPi.m
+++ b/inst/wrapToPi.m
@@ -1,4 +1,4 @@
-## Copyright (C) 2015 Oscar Monerris Belda
+## Copyright (C) 2015-2020 Oscar Monerris Belda
 ## 
 ## This program is free software; you can redistribute it and/or modify it
 ## under the terms of the GNU General Public License as published by
diff --git a/src/aclocal.m4 b/src/aclocal.m4
index 133d264..5722670 100644
--- a/src/aclocal.m4
+++ b/src/aclocal.m4
@@ -1,6 +1,6 @@
-# generated automatically by aclocal 1.14.1 -*- Autoconf -*-
+# generated automatically by aclocal 1.16.1 -*- Autoconf -*-
 
-# Copyright (C) 1996-2013 Free Software Foundation, Inc.
+# Copyright (C) 1996-2018 Free Software Foundation, Inc.
 
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
diff --git a/src/configure b/src/configure
index ee5d3c9..f79fb0a 100755
--- a/src/configure
+++ b/src/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for Octave-Forge mapping package 1.2.0+.
+# Generated by GNU Autoconf 2.69 for Octave-Forge mapping package 1.4.0.
 #
 #
 # Copyright (C) 1992-1996, 1998-2012 Free Software Foundation, Inc.
@@ -576,8 +576,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='Octave-Forge mapping package'
 PACKAGE_TARNAME='octave-forge-mapping-package'
-PACKAGE_VERSION='1.2.0+'
-PACKAGE_STRING='Octave-Forge mapping package 1.2.0+'
+PACKAGE_VERSION='1.4.0'
+PACKAGE_STRING='Octave-Forge mapping package 1.4.0'
 PACKAGE_BUGREPORT=''
 PACKAGE_URL=''
 
@@ -617,6 +617,7 @@ infodir
 docdir
 oldincludedir
 includedir
+runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -695,6 +696,7 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
+runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -947,6 +949,15 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
+  -runstatedir | --runstatedir | --runstatedi | --runstated \
+  | --runstate | --runstat | --runsta | --runst | --runs \
+  | --run | --ru | --r)
+    ac_prev=runstatedir ;;
+  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
+  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
+  | --run=* | --ru=* | --r=*)
+    runstatedir=$ac_optarg ;;
+
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1084,7 +1095,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir
+		libdir localedir mandir runstatedir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1197,7 +1208,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures Octave-Forge mapping package 1.2.0+ to adapt to many kinds of systems.
+\`configure' configures Octave-Forge mapping package 1.4.0 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1237,6 +1248,7 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
+  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
@@ -1259,7 +1271,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of Octave-Forge mapping package 1.2.0+:";;
+     short | recursive ) echo "Configuration of Octave-Forge mapping package 1.4.0:";;
    esac
   cat <<\_ACEOF
 
@@ -1349,7 +1361,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-Octave-Forge mapping package configure 1.2.0+
+Octave-Forge mapping package configure 1.4.0
 generated by GNU Autoconf 2.69
 
 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -1450,7 +1462,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by Octave-Forge mapping package $as_me 1.2.0+, which was
+It was created by Octave-Forge mapping package $as_me 1.4.0, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   $ $0 $@
@@ -3144,7 +3156,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by Octave-Forge mapping package $as_me 1.2.0+, which was
+This file was extended by Octave-Forge mapping package $as_me 1.4.0, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -3206,7 +3218,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-Octave-Forge mapping package config.status 1.2.0+
+Octave-Forge mapping package config.status 1.4.0
 configured by $0, generated by GNU Autoconf 2.69,
   with options \\"\$ac_cs_config\\"
 
diff --git a/src/configure.ac b/src/configure.ac
index 12b1537..8e1d1c4 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -1,5 +1,5 @@
 AC_PREREQ([2.67])
-AC_INIT([Octave-Forge mapping package], [1.2.0+])
+AC_INIT([Octave-Forge mapping package], [1.4.0])
 AC_CONFIG_HEADERS([config.h])
 
 AC_ARG_VAR([MKOCTFILE], [Compiler for Octave dynamic-load modules (default=mkoctfile -Wall)])
diff --git a/src/deg2rad.m.in b/src/deg2rad.m.in
index 2ef0038..97dde71 100644
--- a/src/deg2rad.m.in
+++ b/src/deg2rad.m.in
@@ -1,4 +1,4 @@
-## Copyright (C) 2004 Andrew Collier <abcollier@users.sourceforge.net>
+## Copyright (C) 2004-2020 Andrew Collier <abcollier@users.sourceforge.net>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software
diff --git a/src/gdalread.cc b/src/gdalread.cc
index cdc13f7..92e7fef 100644
--- a/src/gdalread.cc
+++ b/src/gdalread.cc
@@ -1,8 +1,8 @@
 /*
 The MIT License (MIT)
 
-Copyright (C) 2015 Shashank Khare, skhare at hotmail dot com
-Copyright (C) 2015 Philip Nienhuis <prnienhuis@users.sf.net>
+Copyright (C) 2015-2020 Shashank Khare, skhare at hotmail dot com
+Copyright (C) 2015-2020 Philip Nienhuis <prnienhuis@users.sf.net>
 Large parts of the below code originate from http://www.gdal.org/gdal_tutorial.html
 
 Acknowledgement: Snow and Avalanche Studies Establishment, DRDO, Chandigarh, India
diff --git a/src/misc.cpp b/src/misc.cpp
index f0902b1..fc40d4a 100644
--- a/src/misc.cpp
+++ b/src/misc.cpp
@@ -1,6 +1,6 @@
 /*
 The MIT License (MIT)
-Copyright (C) 2015 Shashank Khare
+Copyright (C) 2015-2020 Shashank Khare
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
diff --git a/src/misc.h b/src/misc.h
index a7c8845..fdd66c1 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -1,6 +1,6 @@
 /*
 The MIT License (MIT)
-Copyright (C) 2015 Shashank Khare
+Copyright (C) 2015-2020 Shashank Khare
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
diff --git a/src/rad2deg.m.in b/src/rad2deg.m.in
index da74577..495b89d 100644
--- a/src/rad2deg.m.in
+++ b/src/rad2deg.m.in
@@ -1,4 +1,4 @@
-## Copyright (C) 2004 Andrew Collier <abcollier@users.sourceforge.net>
+## Copyright (C) 2004-2020 Andrew Collier <abcollier@users.sourceforge.net>
 ##
 ## This program is free software; you can redistribute it and/or modify it under
 ## the terms of the GNU General Public License as published by the Free Software