highcharts
Version:
JavaScript charting framework
60 lines (59 loc) • 1.2 kB
JavaScript
/* *
* Orthographic projection
* */
;
/* *
*
* Constants
*
* */
const deg2rad = Math.PI / 180, scale = 63.78460826781007;
/* *
*
* Class
*
* */
class Orthographic {
constructor() {
/* *
*
* Properties
*
* */
this.antimeridianCutting = false;
this.bounds = {
x1: -scale,
x2: scale,
y1: -scale,
y2: scale
};
}
/* *
*
* Functions
*
* */
forward(lonLat) {
const lonDeg = lonLat[0], latDeg = lonLat[1], lat = latDeg * deg2rad, xy = [
Math.cos(lat) * Math.sin(lonDeg * deg2rad) * scale,
Math.sin(lat) * scale
];
if (lonDeg < -90 || lonDeg > 90) {
xy.outside = true;
}
return xy;
}
inverse(xy) {
const x = xy[0] / scale, y = xy[1] / scale, z = Math.sqrt(x * x + y * y), c = Math.asin(z), cSin = Math.sin(c), cCos = Math.cos(c);
return [
Math.atan2(x * cSin, z * cCos) / deg2rad,
Math.asin(z && y * cSin / z) / deg2rad
];
}
}
/* *
*
* Default Export
*
* */
export default Orthographic;