itowns/lib/Core/Geographic/CoordStars.js

A JS/WebGL framework for 3D geospatial data visualization

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports["default"] = void 0;

var _Coordinates = _interopRequireDefault(require("./Coordinates"));

/**
 * Generated On: 2016-02-25
 * Class: CoordStars
 * Description: get coord of stars like earth...
 */
var CoordStars = {
  getSunPosition: function getSunPosition() {
    var m = Math;
    var PI = m.PI;
    var sin = m.sin;
    var cos = m.cos;
    var tan = m.tan;
    var asin = m.asin;
    var atan = m.atan2;
    var rad = PI / 180;
    var e = rad * 23.4397; // obliquity of the Earth

    function toJulian(date) {
      return date.valueOf() / (1000 * 60 * 60 * 24) - 0.5 + 2440588;
    }

    function toDays(date) {
      return toJulian(date) - 2451545;
    }

    function getRightAscension(l, b) {
      return atan(sin(l) * cos(e) - tan(b) * sin(e), cos(l));
    }

    function getDeclination(l, b) {
      return asin(sin(b) * cos(e) + cos(b) * sin(e) * sin(l));
    }

    function getAzimuth(H, phi, dec) {
      return atan(sin(H), cos(H) * sin(phi) - tan(dec) * cos(phi));
    }

    function getAltitude(H, phi, dec) {
      return asin(sin(phi) * sin(dec) + cos(phi) * cos(dec) * cos(H));
    }

    function getSiderealTime(d, lw) {
      return rad * (280.16 + 360.9856235 * d) - lw;
    }

    function getSolarMeanAnomaly(d) {
      return rad * (357.5291 + 0.98560028 * d);
    }

    function getEquationOfCenter(M) {
      return rad * (1.9148 * sin(M) + 0.0200 * sin(2 * M) + 0.0003 * sin(3 * M));
    }

    function getEclipticLongitude(M, C) {
      // perihelion of the Earth
      return M + C + rad * 102.9372 + PI;
    }

    return function (date, lat, lon) {
      var phi = rad * lat;
      var d = toDays(date);
      var M = getSolarMeanAnomaly(d);
      var C = getEquationOfCenter(M);
      var L = getEclipticLongitude(M, C);
      var D = getDeclination(L, 0);
      var A = getRightAscension(L, 0);
      var t = getSiderealTime(d, rad * -lon);
      var H = t - A;
      return {
        EclipticLongitude: L,
        declinaison: D,
        ascension: A,
        H: H,
        SiderealTime: t,
        altitude: getAltitude(H, phi, D),
        azimuth: getAzimuth(H, phi, D) + PI / 2 // + PI// - PI/2 // origin: north !!! not like original Mourner code but more classical ref

      };
    };
  },
  // Return scene coordinate ({x,y,z}) of sun
  getSunPositionInScene: function getSunPositionInScene(date, lat, lon) {
    var sun = CoordStars.getSunPosition()(date, lat, lon);
    var dayMilliSec = 24 * 3600000;
    var longitude = sun.ascension + date % dayMilliSec / dayMilliSec * -360 + 180; // cause midday

    var coSunCarto = new _Coordinates["default"]('EPSG:4326', longitude, lat, 50000000).as('EPSG:4978').toVector3();
    return coSunCarto;
  }
};
var _default = CoordStars;
exports["default"] = _default;