44 lines
1.1 KiB
JavaScript
44 lines
1.1 KiB
JavaScript
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import {LatLng} from '../LatLng';
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import {Bounds} from '../../geometry/Bounds';
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import {Point} from '../../geometry/Point';
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/*
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* @namespace Projection
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* @projection L.Projection.SphericalMercator
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*
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* Spherical Mercator projection — the most common projection for online maps,
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* used by almost all free and commercial tile providers. Assumes that Earth is
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* a sphere. Used by the `EPSG:3857` CRS.
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*/
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var earthRadius = 6378137;
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export var SphericalMercator = {
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R: earthRadius,
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MAX_LATITUDE: 85.0511287798,
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project: function (latlng) {
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var d = Math.PI / 180,
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max = this.MAX_LATITUDE,
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lat = Math.max(Math.min(max, latlng.lat), -max),
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sin = Math.sin(lat * d);
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return new Point(
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this.R * latlng.lng * d,
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this.R * Math.log((1 + sin) / (1 - sin)) / 2);
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},
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unproject: function (point) {
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var d = 180 / Math.PI;
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return new LatLng(
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(2 * Math.atan(Math.exp(point.y / this.R)) - (Math.PI / 2)) * d,
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point.x * d / this.R);
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},
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bounds: (function () {
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var d = earthRadius * Math.PI;
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return new Bounds([-d, -d], [d, d]);
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})()
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};
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