node-red-contrib-tak-registration/node_modules/d3-geo/src/projection/stereographic.js

A Node-RED node to register to TAK and to help wrap files as datapackages to send to TAK

import {atan, cos, sin} from "../math";
import {azimuthalInvert} from "./azimuthal";
import projection from "./index";

export function stereographicRaw(x, y) {
  var cy = cos(y), k = 1 + cos(x) * cy;
  return [cy * sin(x) / k, sin(y) / k];
}

stereographicRaw.invert = azimuthalInvert(function(z) {
  return 2 * atan(z);
});

export default function() {
  return projection(stereographicRaw)
      .scale(250)
      .clipAngle(142);
}