49 lines
1.2 KiB
JavaScript
49 lines
1.2 KiB
JavaScript
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import adjust_lon from '../common/adjust_lon';
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import adjust_lat from '../common/adjust_lat';
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export function init() {
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this.x0 = this.x0 || 0;
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this.y0 = this.y0 || 0;
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this.lat0 = this.lat0 || 0;
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this.long0 = this.long0 || 0;
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this.lat_ts = this.lat_ts || 0;
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this.title = this.title || "Equidistant Cylindrical (Plate Carre)";
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this.rc = Math.cos(this.lat_ts);
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}
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// forward equations--mapping lat,long to x,y
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// -----------------------------------------------------------------
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export function forward(p) {
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var lon = p.x;
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var lat = p.y;
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var dlon = adjust_lon(lon - this.long0);
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var dlat = adjust_lat(lat - this.lat0);
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p.x = this.x0 + (this.a * dlon * this.rc);
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p.y = this.y0 + (this.a * dlat);
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return p;
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}
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// inverse equations--mapping x,y to lat/long
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// -----------------------------------------------------------------
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export function inverse(p) {
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var x = p.x;
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var y = p.y;
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p.x = adjust_lon(this.long0 + ((x - this.x0) / (this.a * this.rc)));
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p.y = adjust_lat(this.lat0 + ((y - this.y0) / (this.a)));
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return p;
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}
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export var names = ["Equirectangular", "Equidistant_Cylindrical", "eqc"];
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export default {
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init: init,
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forward: forward,
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inverse: inverse,
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names: names
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};
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