1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
import {abs, atan, atan2, cos, epsilon, halfPi, log, pow, sign, sin, sqrt, tan} from "../math.js";
import {conicProjection} from "./conic.js";
import {mercatorRaw} from "./mercator.js";
function tany(y) {
return tan((halfPi + y) / 2);
}
export function conicConformalRaw(y0, y1) {
var cy0 = cos(y0),
n = y0 === y1 ? sin(y0) : log(cy0 / cos(y1)) / log(tany(y1) / tany(y0)),
f = cy0 * pow(tany(y0), n) / n;
if (!n) return mercatorRaw;
function project(x, y) {
if (f > 0) { if (y < -halfPi + epsilon) y = -halfPi + epsilon; }
else { if (y > halfPi - epsilon) y = halfPi - epsilon; }
var r = f / pow(tany(y), n);
return [r * sin(n * x), f - r * cos(n * x)];
}
project.invert = function(x, y) {
var fy = f - y, r = sign(n) * sqrt(x * x + fy * fy);
return [atan2(x, abs(fy)) / n * sign(fy), 2 * atan(pow(f / r, 1 / n)) - halfPi];
};
return project;
}
export default function() {
return conicProjection(conicConformalRaw)
.scale(109.5)
.parallels([30, 30]);
}
|
