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openlayers

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Build tools and sources for developing OpenLayers based mapping applications

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goog.provide('ol.proj.EPSG3857'); goog.require('ol'); goog.require('ol.math'); goog.require('ol.proj'); goog.require('ol.proj.Projection'); goog.require('ol.proj.Units'); /** * @classdesc * Projection object for web/spherical Mercator (EPSG:3857). * * @constructor * @extends {ol.proj.Projection} * @param {string} code Code. * @private */ ol.proj.EPSG3857_ = function(code) { ol.proj.Projection.call(this, { code: code, units: ol.proj.Units.METERS, extent: ol.proj.EPSG3857.EXTENT, global: true, worldExtent: ol.proj.EPSG3857.WORLD_EXTENT, getPointResolution: function(resolution, point) { return resolution / ol.math.cosh(point[1] / ol.proj.EPSG3857.RADIUS); } }); }; ol.inherits(ol.proj.EPSG3857_, ol.proj.Projection); /** * @const * @type {number} */ ol.proj.EPSG3857.RADIUS = 6378137; /** * @const * @type {number} */ ol.proj.EPSG3857.HALF_SIZE = Math.PI * ol.proj.EPSG3857.RADIUS; /** * @const * @type {ol.Extent} */ ol.proj.EPSG3857.EXTENT = [ -ol.proj.EPSG3857.HALF_SIZE, -ol.proj.EPSG3857.HALF_SIZE, ol.proj.EPSG3857.HALF_SIZE, ol.proj.EPSG3857.HALF_SIZE ]; /** * @const * @type {ol.Extent} */ ol.proj.EPSG3857.WORLD_EXTENT = [-180, -85, 180, 85]; /** * Lists several projection codes with the same meaning as EPSG:3857. * * @type {Array.<string>} */ ol.proj.EPSG3857.CODES = [ 'EPSG:3857', 'EPSG:102100', 'EPSG:102113', 'EPSG:900913', 'urn:ogc:def:crs:EPSG:6.18:3:3857', 'urn:ogc:def:crs:EPSG::3857', 'http://www.opengis.net/gml/srs/epsg.xml#3857' ]; /** * Projections equal to EPSG:3857. * * @const * @type {Array.<ol.proj.Projection>} */ ol.proj.EPSG3857.PROJECTIONS = ol.proj.EPSG3857.CODES.map(function(code) { return new ol.proj.EPSG3857_(code); }); /** * Transformation from EPSG:4326 to EPSG:3857. * * @param {Array.<number>} input Input array of coordinate values. * @param {Array.<number>=} opt_output Output array of coordinate values. * @param {number=} opt_dimension Dimension (default is `2`). * @return {Array.<number>} Output array of coordinate values. */ ol.proj.EPSG3857.fromEPSG4326 = function(input, opt_output, opt_dimension) { var length = input.length, dimension = opt_dimension > 1 ? opt_dimension : 2, output = opt_output; if (output === undefined) { if (dimension > 2) { // preserve values beyond second dimension output = input.slice(); } else { output = new Array(length); } } ol.DEBUG && console.assert(output.length % dimension === 0, 'modulus of output.length with dimension should be 0'); var halfSize = ol.proj.EPSG3857.HALF_SIZE; for (var i = 0; i < length; i += dimension) { output[i] = halfSize * input[i] / 180; var y = ol.proj.EPSG3857.RADIUS * Math.log(Math.tan(Math.PI * (input[i + 1] + 90) / 360)); if (y > halfSize) { y = halfSize; } else if (y < -halfSize) { y = -halfSize; } output[i + 1] = y; } return output; }; /** * Transformation from EPSG:3857 to EPSG:4326. * * @param {Array.<number>} input Input array of coordinate values. * @param {Array.<number>=} opt_output Output array of coordinate values. * @param {number=} opt_dimension Dimension (default is `2`). * @return {Array.<number>} Output array of coordinate values. */ ol.proj.EPSG3857.toEPSG4326 = function(input, opt_output, opt_dimension) { var length = input.length, dimension = opt_dimension > 1 ? opt_dimension : 2, output = opt_output; if (output === undefined) { if (dimension > 2) { // preserve values beyond second dimension output = input.slice(); } else { output = new Array(length); } } ol.DEBUG && console.assert(output.length % dimension === 0, 'modulus of output.length with dimension should be 0'); for (var i = 0; i < length; i += dimension) { output[i] = 180 * input[i] / ol.proj.EPSG3857.HALF_SIZE; output[i + 1] = 360 * Math.atan( Math.exp(input[i + 1] / ol.proj.EPSG3857.RADIUS)) / Math.PI - 90; } return output; };