gridtracker/package.nw/lib/shadow.js

/**

**/
(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global.GeoJSONTerminator = factory());
}(this, (function () { 'use strict';

  function julian(date) {
    /* Calculate the present UTC Julian Date. Function is valid after
     * the beginning of the UNIX epoch 1970-01-01 and ignores leap
     * seconds. */
    return (date / 86400000) + 2440587.5;
  }

  function GMST(julianDay) {
    /* Calculate Greenwich Mean Sidereal Time according to
       http://aa.usno.navy.mil/faq/docs/GAST.php */
    var d = julianDay - 2451545.0;
    // Low precision equation is good enough for our purposes.
    return (18.697374558 + 24.06570982441908 * d) % 24;
  }

  class Terminator {
    constructor(options={resolution: 1}) {
      this.options = options;
      this.version = '0.1.0';
      this._R2D = 180 / Math.PI;
      this._D2R = Math.PI / 180;
      //this.options.resolution = options.resolution || this.options.resolution;
      // this.options.time = options.time;
      var latLngs = this._compute(this.options.time);
      return this._toGeoJSON(latLngs);
    }

    setTime(date) {
      this.options.time = date;
      var latLngs = this._compute(date);
      return this._toGeoJSON(latLngs);
    }

    _toGeoJSON(latLngs) {
      /* Return 'pseudo' GeoJSON representation of the coordinates
        Why 'pseudo'?
        Coordinates longitude range go from -360 to 360
        whereas it should be -180, + 180
        API like OpenLayers or Leaflet can consume them although invalid
        from GeoJSON spec
        In this case, use something like GDAL/OGR to clip to a valid range with
        ogr2ogr -f "GeoJSON" output.geojson input.geojson \
        -clipsrc -180 90 180 90
      */
       return {
            "type": "Feature",
            "properties": {},
            "geometry": {
              "type": "Polygon",
              "coordinates": [
                [
                  ...latLngs.map(latLng => {
                    return [latLng[1], latLng[0]];
                  }),
                  [latLngs[0][1], latLngs[0][0]]
                ].slice().reverse()
              ]
            }
      }
    }

    _sunEclipticPosition (julianDay) {
      /* Compute the position of the Sun in ecliptic coordinates at
         julianDay.  Following
         http://en.wikipedia.org/wiki/Position_of_the_Sun */
      // Days since start of J2000.0
      var n = julianDay - 2451545.0;
      // mean longitude of the Sun
      var L = 280.460 + 0.9856474 * n;
      L %= 360;
      // mean anomaly of the Sun
      var g = 357.528 + 0.9856003 * n;
      g %= 360;
      // ecliptic longitude of Sun
      var lambda = L + 1.915 * Math.sin(g * this._D2R) +
        0.02 * Math.sin(2 * g * this._D2R);

      return {lambda: lambda};
    }

    _eclipticObliquity (julianDay) {
      // Following the short term expression in
      // http://en.wikipedia.org/wiki/Axial_tilt#Obliquity_of_the_ecliptic_.28Earth.27s_axial_tilt.29
      var n = julianDay - 2451545.0;
      // Julian centuries since J2000.0
      var T = n / 36525;
      var epsilon = 23.43929111 -
        T * (46.836769 / 3600
          - T * (0.0001831 / 3600
            + T * (0.00200340 / 3600
              - T * (0.576e-6 / 3600
                - T * 4.34e-8 / 3600))));
      return epsilon;
    }
	_jday (date) {
        return (date.getTime() / 86400000.0) + 2440587.5;
    }
    _calculatePositionOfSun (date) {
        date = (date instanceof Date) ? date : new Date();

        var rad = 0.017453292519943295;

        // based on NOAA solar calculations
        var ms_past_midnight = ((date.getUTCHours() * 60 + date.getUTCMinutes()) * 60 + date.getUTCSeconds()) * 1000 + date.getUTCMilliseconds();
        var jc = (this._jday(date) - 2451545)/36525;
        var mean_long_sun = (280.46646+jc*(36000.76983+jc*0.0003032)) % 360;
        var mean_anom_sun = 357.52911+jc*(35999.05029-0.0001537*jc);
        var sun_eq = Math.sin(rad*mean_anom_sun)*(1.914602-jc*(0.004817+0.000014*jc))+Math.sin(rad*2*mean_anom_sun)*(0.019993-0.000101*jc)+Math.sin(rad*3*mean_anom_sun)*0.000289;
        var sun_true_long = mean_long_sun + sun_eq;
        var sun_app_long = sun_true_long - 0.00569 - 0.00478*Math.sin(rad*125.04-1934.136*jc);
        var mean_obliq_ecliptic = 23+(26+((21.448-jc*(46.815+jc*(0.00059-jc*0.001813))))/60)/60;
        var obliq_corr = mean_obliq_ecliptic + 0.00256*Math.cos(rad*125.04-1934.136*jc);

        var lat = Math.asin(Math.sin(rad*obliq_corr)*Math.sin(rad*sun_app_long)) / rad;

        var eccent = 0.016708634-jc*(0.000042037+0.0000001267*jc);
        var y = Math.tan(rad*(obliq_corr/2))*Math.tan(rad*(obliq_corr/2));
        var rq_of_time = 4*((y*Math.sin(2*rad*mean_long_sun)-2*eccent*Math.sin(rad*mean_anom_sun)+4*eccent*y*Math.sin(rad*mean_anom_sun)*Math.cos(2*rad*mean_long_sun)-0.5*y*y*Math.sin(4*rad*mean_long_sun)-1.25*eccent*eccent*Math.sin(2*rad*mean_anom_sun))/rad);
        var true_solar_time_in_deg = ((ms_past_midnight+rq_of_time*60000) % 86400000) / 240000;

        var lng = -((true_solar_time_in_deg < 0) ? true_solar_time_in_deg + 180 : true_solar_time_in_deg - 180);

        return [lng,lat];
    }

    _sunEquatorialPosition (sunEclLng, eclObliq) {
      /* Compute the Sun's equatorial position from its ecliptic
       * position. Inputs are expected in degrees. Outputs are in
       * degrees as well. */
      var alpha = Math.atan(Math.cos(eclObliq * this._D2R)
        * Math.tan(sunEclLng * this._D2R)) * this._R2D;
      var delta = Math.asin(Math.sin(eclObliq * this._D2R)
        * Math.sin(sunEclLng * this._D2R)) * this._R2D;

      var lQuadrant = Math.floor(sunEclLng / 90) * 90;
      var raQuadrant = Math.floor(alpha / 90) * 90;
      alpha = alpha + (lQuadrant - raQuadrant);

      return {alpha: alpha, delta: delta};
    }

    _hourAngle (lng, sunPos, gst) {
      /* Compute the hour angle of the sun for a longitude on
       * Earth. Return the hour angle in degrees. */
      var lst = gst + lng / 15;
      return lst * 15 - sunPos.alpha;
    }

    _latitude (ha, sunPos) {
      /* For a given hour angle and sun position, compute the
       * latitude of the terminator in degrees. */
      var lat = Math.atan(-Math.cos(ha * this._D2R) /
        Math.tan(sunPos.delta * this._D2R)) * this._R2D;
      return lat;
    }

    _compute (time) {
      var today = time ? new Date(time) : new Date();
      var julianDay = julian(today);
      var gst = GMST(julianDay);
      var latLng = [];
      var startMinus = -360;

      var sunEclPos = this._sunEclipticPosition(julianDay);
      var eclObliq = this._eclipticObliquity(julianDay);
      var sunEqPos = this._sunEquatorialPosition(sunEclPos.lambda, eclObliq);
      for (var i = 0; i <= 720 * this.options.resolution; i++) {
        var lng = startMinus + i / this.options.resolution;
        var ha = this._hourAngle(lng, sunEqPos, gst);
        latLng[i+1 ] = [this._latitude(ha, sunEqPos), lng ];
      }
      if (sunEqPos.delta < 0) {
       latLng[0] = [90, startMinus];
        latLng[latLng.length] = [90, 360];
      } else {
        latLng[0] = [-90, startMinus];
        latLng[latLng.length] = [-90, 360];
      }
      return latLng;
    }
  }
  function terminator(options) {
    return new Terminator(options);
  }

  return terminator;

})));


var dayNight = {
    map: null,
	vectorLayer:null,

    init: function (map) {
        this.map = map;

		var geoJSON = new GeoJSONTerminator();

		this.vectorSource = new ol.source.Vector({
          features: (new ol.format.GeoJSON()).readFeatures(geoJSON, {
            featureProjection: 'EPSG:3857'
          })
        });

        this.vectorLayer = new ol.layer.Vector({
            source: this.vectorSource,
			style: new ol.style.Style({
          fill: new ol.style.Fill({
            color: 'rgb(0,0,0)'
          }),
          stroke: null
        }),
			opacity: Number(g_mapSettings.shadow),
            zIndex: 0
        });
		this.map.getLayers().insertAt(1, this.vectorLayer);

    },
    refresh: function () {
				var circleStyle = new ol.style.Style({
					fill: new ol.style.Fill({
						  color: 'rgb(0,0,0)'
					})
				});
				 this.vectorLayer.setStyle(circleStyle);
				 this.vectorLayer.setOpacity(Number(g_mapSettings.shadow));
				 this.vectorSource.clear();

				this.vectorSource.addFeature(
					(new ol.format.GeoJSON()).readFeature(new GeoJSONTerminator(), {
						featureProjection: 'EPSG:3857'
					})
					);
				var point =	 ol.proj.fromLonLat([g_myLon, g_myLat]);
				var arr = this.vectorSource.getFeaturesAtCoordinate(point);
				return (arr.length > 0?true:false);

    },

    show: function () {
		this.vectorLayer.setVisible(true);
		return this.refresh();
    },
    hide: function () {
    	this.vectorLayer.setVisible(false);
    },
    isVisible: function () {
        return this.vectorLayer.getVisible();
    }
};

var moonLayer = {
    map: null,
	vectorLayer:null,
	icon: null,
	pin: null,
    init: function (map) {
        this.map = map;

		this.icon = new ol.style.Icon({
				src: "./img/luna.png",
				anchorYUnits: 'pixels',
				anchorXUnits: 'pixels',
				anchor: [255,255],
				scale: 0.10,
				opacity: 0.5
			});


		this.pin = iconFeature( ol.proj.fromLonLat(subLunar(timeNowSec()).ll) , this.icon, 0);
		this.pin.size = 99;
		this.vectorSource = new ol.source.Vector({});

        this.vectorLayer = new ol.layer.Vector({
            source: this.vectorSource,
            zIndex: 30
        });
		this.map.getLayers().insertAt(1, this.vectorLayer);

    },
	future: function (now) {
		var r = 0;
		var x = 25;
		var i = 3600;
		var data = Array();
		for ( r = 0; r < x; r++ )
		{
			data.push( subLunar(now + (r*i)).ll );
		}
		line = [];

		var lonOff = 0;
		var lastc = 0;

		for (var i = 0; i < data.length; i++)
		{
		  var c = data[i];
		  if (isNaN(c[0])) {
			continue;
		  }
		  if (Math.abs(lastc - c[0]) > 270) {
			// Wrapped
		if (c[0] < lastc) {
		  lonOff += 360;
		} else {
		  lonOff -= 360;
		}
		  }
		  lastc = c[0];
		  line.push(ol.proj.fromLonLat([ c[0] + lonOff, c[1]]));
		}

		if (line.length == 0) {
		line.push(ol.proj.fromLonLat(start));
		}


		line = new ol.geom.LineString(line);
		var feature = new ol.Feature({ geometry: line, name: 'moonFlight' });


		feature.setStyle(new ol.style.Style({
			stroke: new ol.style.Stroke({ color: "#FFF", width: 1}) }));

		return feature;

	},
    refresh: function () {
		this.vectorSource.clear();
		if (  g_appSettings.moonTrack == 1 )
		{
			now = timeNowSec();
			if ( g_appSettings.moonPath == 1 )
				this.vectorSource.addFeature(this.future(now));
			this.pin = iconFeature( ol.proj.fromLonLat(subLunar(now).ll) , this.icon, 0);
			this.pin.size = 99;
			this.vectorSource.addFeature(this.pin);
		}

    },

    show: function () {
		this.refresh();
		this.vectorLayer.setVisible(true);
		lunaButonImg.style.webkitFilter = "brightness(100%)";
    },
    hide: function () {
    	this.vectorLayer.setVisible(false);
		lunaButonImg.style.webkitFilter = "brightness(50%)";
    },
    isVisible: function () {
        return this.vectorLayer.getVisible();
    }
};