470 lines
16 KiB
JavaScript
470 lines
16 KiB
JavaScript
goog.provide('ol.proj');
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goog.require('ol');
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goog.require('ol.extent');
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goog.require('ol.proj.Projection');
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goog.require('ol.proj.Units');
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goog.require('ol.proj.proj4');
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goog.require('ol.proj.projections');
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goog.require('ol.proj.transforms');
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goog.require('ol.sphere.NORMAL');
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/**
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* Meters per unit lookup table.
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* @const
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* @type {Object.<ol.proj.Units, number>}
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* @api stable
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*/
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ol.proj.METERS_PER_UNIT = ol.proj.Units.METERS_PER_UNIT;
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if (ol.ENABLE_PROJ4JS) {
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/**
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* Register proj4. If not explicitly registered, it will be assumed that
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* proj4js will be loaded in the global namespace. For example in a
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* browserify ES6 environment you could use:
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*
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* import ol from 'openlayers';
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* import proj4 from 'proj4';
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* ol.proj.setProj4(proj4);
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*
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* @param {proj4} proj4 Proj4.
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* @api
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*/
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ol.proj.setProj4 = function(proj4) {
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ol.proj.proj4.set(proj4);
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};
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}
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/**
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* Get the resolution of the point in degrees or distance units.
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* For projections with degrees as the unit this will simply return the
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* provided resolution. For other projections the point resolution is
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* estimated by transforming the 'point' pixel to EPSG:4326,
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* measuring its width and height on the normal sphere,
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* and taking the average of the width and height.
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* @param {ol.proj.Projection} projection The projection.
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* @param {number} resolution Nominal resolution in projection units.
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* @param {ol.Coordinate} point Point to find adjusted resolution at.
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* @return {number} Point resolution at point in projection units.
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* @api
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*/
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ol.proj.getPointResolution = function(projection, resolution, point) {
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var pointResolution;
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var getter = projection.getPointResolutionFunc();
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if (getter) {
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pointResolution = getter(resolution, point);
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} else {
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var units = projection.getUnits();
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if (units == ol.proj.Units.DEGREES) {
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pointResolution = resolution;
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} else {
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// Estimate point resolution by transforming the center pixel to EPSG:4326,
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// measuring its width and height on the normal sphere, and taking the
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// average of the width and height.
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var toEPSG4326 = ol.proj.getTransformFromProjections(projection, ol.proj.get('EPSG:4326'));
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var vertices = [
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point[0] - resolution / 2, point[1],
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point[0] + resolution / 2, point[1],
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point[0], point[1] - resolution / 2,
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point[0], point[1] + resolution / 2
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];
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vertices = toEPSG4326(vertices, vertices, 2);
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var width = ol.sphere.NORMAL.haversineDistance(
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vertices.slice(0, 2), vertices.slice(2, 4));
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var height = ol.sphere.NORMAL.haversineDistance(
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vertices.slice(4, 6), vertices.slice(6, 8));
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pointResolution = (width + height) / 2;
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var metersPerUnit = projection.getMetersPerUnit();
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if (metersPerUnit !== undefined) {
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pointResolution /= metersPerUnit;
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}
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}
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}
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return pointResolution;
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};
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/**
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* Registers transformation functions that don't alter coordinates. Those allow
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* to transform between projections with equal meaning.
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*
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* @param {Array.<ol.proj.Projection>} projections Projections.
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* @api
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*/
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ol.proj.addEquivalentProjections = function(projections) {
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ol.proj.addProjections(projections);
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projections.forEach(function(source) {
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projections.forEach(function(destination) {
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if (source !== destination) {
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ol.proj.transforms.add(source, destination, ol.proj.cloneTransform);
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}
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});
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});
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};
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/**
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* Registers transformation functions to convert coordinates in any projection
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* in projection1 to any projection in projection2.
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*
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* @param {Array.<ol.proj.Projection>} projections1 Projections with equal
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* meaning.
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* @param {Array.<ol.proj.Projection>} projections2 Projections with equal
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* meaning.
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* @param {ol.TransformFunction} forwardTransform Transformation from any
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* projection in projection1 to any projection in projection2.
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* @param {ol.TransformFunction} inverseTransform Transform from any projection
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* in projection2 to any projection in projection1..
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*/
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ol.proj.addEquivalentTransforms = function(projections1, projections2, forwardTransform, inverseTransform) {
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projections1.forEach(function(projection1) {
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projections2.forEach(function(projection2) {
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ol.proj.transforms.add(projection1, projection2, forwardTransform);
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ol.proj.transforms.add(projection2, projection1, inverseTransform);
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});
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});
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};
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/**
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* Add a Projection object to the list of supported projections that can be
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* looked up by their code.
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*
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* @param {ol.proj.Projection} projection Projection instance.
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* @api stable
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*/
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ol.proj.addProjection = function(projection) {
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ol.proj.projections.add(projection.getCode(), projection);
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ol.proj.transforms.add(projection, projection, ol.proj.cloneTransform);
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};
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/**
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* @param {Array.<ol.proj.Projection>} projections Projections.
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*/
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ol.proj.addProjections = function(projections) {
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var addedProjections = [];
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projections.forEach(function(projection) {
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addedProjections.push(ol.proj.addProjection(projection));
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});
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};
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/**
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* Clear all cached projections and transforms.
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*/
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ol.proj.clearAllProjections = function() {
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ol.proj.projections.clear();
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ol.proj.transforms.clear();
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};
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/**
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* @param {ol.proj.Projection|string|undefined} projection Projection.
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* @param {string} defaultCode Default code.
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* @return {ol.proj.Projection} Projection.
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*/
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ol.proj.createProjection = function(projection, defaultCode) {
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if (!projection) {
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return ol.proj.get(defaultCode);
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} else if (typeof projection === 'string') {
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return ol.proj.get(projection);
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} else {
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return /** @type {ol.proj.Projection} */ (projection);
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}
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};
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/**
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* Registers coordinate transform functions to convert coordinates between the
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* source projection and the destination projection.
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* The forward and inverse functions convert coordinate pairs; this function
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* converts these into the functions used internally which also handle
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* extents and coordinate arrays.
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*
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* @param {ol.ProjectionLike} source Source projection.
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* @param {ol.ProjectionLike} destination Destination projection.
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* @param {function(ol.Coordinate): ol.Coordinate} forward The forward transform
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* function (that is, from the source projection to the destination
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* projection) that takes a {@link ol.Coordinate} as argument and returns
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* the transformed {@link ol.Coordinate}.
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* @param {function(ol.Coordinate): ol.Coordinate} inverse The inverse transform
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* function (that is, from the destination projection to the source
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* projection) that takes a {@link ol.Coordinate} as argument and returns
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* the transformed {@link ol.Coordinate}.
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* @api stable
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*/
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ol.proj.addCoordinateTransforms = function(source, destination, forward, inverse) {
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var sourceProj = ol.proj.get(source);
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var destProj = ol.proj.get(destination);
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ol.proj.transforms.add(sourceProj, destProj,
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ol.proj.createTransformFromCoordinateTransform(forward));
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ol.proj.transforms.add(destProj, sourceProj,
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ol.proj.createTransformFromCoordinateTransform(inverse));
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};
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/**
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* Creates a {@link ol.TransformFunction} from a simple 2D coordinate transform
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* function.
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* @param {function(ol.Coordinate): ol.Coordinate} transform Coordinate
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* transform.
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* @return {ol.TransformFunction} Transform function.
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*/
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ol.proj.createTransformFromCoordinateTransform = function(transform) {
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return (
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/**
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* @param {Array.<number>} input Input.
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* @param {Array.<number>=} opt_output Output.
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* @param {number=} opt_dimension Dimension.
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* @return {Array.<number>} Output.
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*/
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function(input, opt_output, opt_dimension) {
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var length = input.length;
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var dimension = opt_dimension !== undefined ? opt_dimension : 2;
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var output = opt_output !== undefined ? opt_output : new Array(length);
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var point, i, j;
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for (i = 0; i < length; i += dimension) {
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point = transform([input[i], input[i + 1]]);
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output[i] = point[0];
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output[i + 1] = point[1];
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for (j = dimension - 1; j >= 2; --j) {
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output[i + j] = input[i + j];
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}
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}
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return output;
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});
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};
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/**
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* Transforms a coordinate from longitude/latitude to a different projection.
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* @param {ol.Coordinate} coordinate Coordinate as longitude and latitude, i.e.
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* an array with longitude as 1st and latitude as 2nd element.
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* @param {ol.ProjectionLike=} opt_projection Target projection. The
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* default is Web Mercator, i.e. 'EPSG:3857'.
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* @return {ol.Coordinate} Coordinate projected to the target projection.
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* @api stable
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*/
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ol.proj.fromLonLat = function(coordinate, opt_projection) {
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return ol.proj.transform(coordinate, 'EPSG:4326',
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opt_projection !== undefined ? opt_projection : 'EPSG:3857');
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};
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/**
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* Transforms a coordinate to longitude/latitude.
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* @param {ol.Coordinate} coordinate Projected coordinate.
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* @param {ol.ProjectionLike=} opt_projection Projection of the coordinate.
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* The default is Web Mercator, i.e. 'EPSG:3857'.
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* @return {ol.Coordinate} Coordinate as longitude and latitude, i.e. an array
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* with longitude as 1st and latitude as 2nd element.
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* @api stable
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*/
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ol.proj.toLonLat = function(coordinate, opt_projection) {
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return ol.proj.transform(coordinate,
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opt_projection !== undefined ? opt_projection : 'EPSG:3857', 'EPSG:4326');
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};
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/**
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* Fetches a Projection object for the code specified.
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*
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* @param {ol.ProjectionLike} projectionLike Either a code string which is
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* a combination of authority and identifier such as "EPSG:4326", or an
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* existing projection object, or undefined.
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* @return {ol.proj.Projection} Projection object, or null if not in list.
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* @api stable
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*/
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ol.proj.get = function(projectionLike) {
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var projection = null;
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if (projectionLike instanceof ol.proj.Projection) {
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projection = projectionLike;
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} else if (typeof projectionLike === 'string') {
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var code = projectionLike;
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projection = ol.proj.projections.get(code);
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if (ol.ENABLE_PROJ4JS) {
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var proj4js = ol.proj.proj4.get();
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if (!projection && typeof proj4js == 'function' &&
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proj4js.defs(code) !== undefined) {
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projection = new ol.proj.Projection({code: code});
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ol.proj.addProjection(projection);
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}
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}
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}
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return projection;
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};
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/**
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* Checks if two projections are the same, that is every coordinate in one
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* projection does represent the same geographic point as the same coordinate in
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* the other projection.
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*
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* @param {ol.proj.Projection} projection1 Projection 1.
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* @param {ol.proj.Projection} projection2 Projection 2.
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* @return {boolean} Equivalent.
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* @api
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*/
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ol.proj.equivalent = function(projection1, projection2) {
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if (projection1 === projection2) {
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return true;
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}
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var equalUnits = projection1.getUnits() === projection2.getUnits();
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if (projection1.getCode() === projection2.getCode()) {
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return equalUnits;
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} else {
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var transformFn = ol.proj.getTransformFromProjections(
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projection1, projection2);
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return transformFn === ol.proj.cloneTransform && equalUnits;
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}
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};
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/**
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* Given the projection-like objects, searches for a transformation
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* function to convert a coordinates array from the source projection to the
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* destination projection.
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*
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* @param {ol.ProjectionLike} source Source.
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* @param {ol.ProjectionLike} destination Destination.
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* @return {ol.TransformFunction} Transform function.
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* @api stable
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*/
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ol.proj.getTransform = function(source, destination) {
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var sourceProjection = ol.proj.get(source);
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var destinationProjection = ol.proj.get(destination);
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return ol.proj.getTransformFromProjections(
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sourceProjection, destinationProjection);
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};
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/**
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* Searches in the list of transform functions for the function for converting
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* coordinates from the source projection to the destination projection.
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*
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* @param {ol.proj.Projection} sourceProjection Source Projection object.
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* @param {ol.proj.Projection} destinationProjection Destination Projection
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* object.
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* @return {ol.TransformFunction} Transform function.
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*/
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ol.proj.getTransformFromProjections = function(sourceProjection, destinationProjection) {
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var sourceCode = sourceProjection.getCode();
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var destinationCode = destinationProjection.getCode();
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var transform = ol.proj.transforms.get(sourceCode, destinationCode);
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if (ol.ENABLE_PROJ4JS && !transform) {
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var proj4js = ol.proj.proj4.get();
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if (typeof proj4js == 'function') {
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var sourceDef = proj4js.defs(sourceCode);
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var destinationDef = proj4js.defs(destinationCode);
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if (sourceDef !== undefined && destinationDef !== undefined) {
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if (sourceDef === destinationDef) {
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ol.proj.addEquivalentProjections([destinationProjection, sourceProjection]);
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} else {
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var proj4Transform = proj4js(destinationCode, sourceCode);
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ol.proj.addCoordinateTransforms(destinationProjection, sourceProjection,
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proj4Transform.forward, proj4Transform.inverse);
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}
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transform = ol.proj.transforms.get(sourceCode, destinationCode);
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}
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}
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}
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if (!transform) {
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transform = ol.proj.identityTransform;
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}
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return transform;
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};
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/**
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* @param {Array.<number>} input Input coordinate array.
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* @param {Array.<number>=} opt_output Output array of coordinate values.
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* @param {number=} opt_dimension Dimension.
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* @return {Array.<number>} Input coordinate array (same array as input).
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*/
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ol.proj.identityTransform = function(input, opt_output, opt_dimension) {
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if (opt_output !== undefined && input !== opt_output) {
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for (var i = 0, ii = input.length; i < ii; ++i) {
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opt_output[i] = input[i];
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}
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input = opt_output;
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}
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return input;
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};
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/**
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* @param {Array.<number>} input Input coordinate array.
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* @param {Array.<number>=} opt_output Output array of coordinate values.
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* @param {number=} opt_dimension Dimension.
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* @return {Array.<number>} Output coordinate array (new array, same coordinate
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* values).
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*/
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ol.proj.cloneTransform = function(input, opt_output, opt_dimension) {
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var output;
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if (opt_output !== undefined) {
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for (var i = 0, ii = input.length; i < ii; ++i) {
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opt_output[i] = input[i];
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}
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output = opt_output;
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} else {
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output = input.slice();
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}
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return output;
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};
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/**
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* Transforms a coordinate from source projection to destination projection.
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* This returns a new coordinate (and does not modify the original).
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*
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* See {@link ol.proj.transformExtent} for extent transformation.
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* See the transform method of {@link ol.geom.Geometry} and its subclasses for
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* geometry transforms.
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*
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* @param {ol.Coordinate} coordinate Coordinate.
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* @param {ol.ProjectionLike} source Source projection-like.
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* @param {ol.ProjectionLike} destination Destination projection-like.
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* @return {ol.Coordinate} Coordinate.
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* @api stable
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*/
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ol.proj.transform = function(coordinate, source, destination) {
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var transformFn = ol.proj.getTransform(source, destination);
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return transformFn(coordinate, undefined, coordinate.length);
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};
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/**
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* Transforms an extent from source projection to destination projection. This
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* returns a new extent (and does not modify the original).
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*
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* @param {ol.Extent} extent The extent to transform.
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* @param {ol.ProjectionLike} source Source projection-like.
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* @param {ol.ProjectionLike} destination Destination projection-like.
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* @return {ol.Extent} The transformed extent.
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* @api stable
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*/
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ol.proj.transformExtent = function(extent, source, destination) {
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var transformFn = ol.proj.getTransform(source, destination);
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return ol.extent.applyTransform(extent, transformFn);
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};
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/**
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* Transforms the given point to the destination projection.
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*
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* @param {ol.Coordinate} point Point.
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* @param {ol.proj.Projection} sourceProjection Source projection.
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* @param {ol.proj.Projection} destinationProjection Destination projection.
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* @return {ol.Coordinate} Point.
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*/
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ol.proj.transformWithProjections = function(point, sourceProjection, destinationProjection) {
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var transformFn = ol.proj.getTransformFromProjections(
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sourceProjection, destinationProjection);
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return transformFn(point);
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};
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