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Make transform functions work with arrays

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Instead of working with ol.Coordinate instances, transform functions work with arrays.  This is in anticipation of using transform functions to transform large arrays of vertex coordinate values.  The ol.projection.transform and ol.projection.transformWithCodes are slightly more convenient functions for dealing with ol.Coordinate instances.  Whether we make this more consistent with the use of functions returned by ol.projection.getTransform is up for discussion.
This commit is contained in:
Tim Schaub
2013-03-03 19:27:57 +01:00
parent 0df692e159
commit 7a5e6a06d8
8 changed files with 163 additions and 57 deletions
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src/ol/projection/epsg3857.js
+40 -15
View File
@@ -1,7 +1,6 @@
goog.provide('ol.projection.EPSG3857');
goog.require('goog.array');
goog.require('ol.Coordinate');
goog.require('ol.Extent');
goog.require('ol.Projection');
goog.require('ol.ProjectionUnits');
@@ -73,26 +72,52 @@ ol.projection.EPSG3857.PROJECTIONS = goog.array.map(
/**
* Transformation from EPSG:4326 to EPSG:3857.
*
* @param {ol.Coordinate} point Point.
* @return {ol.Coordinate} Point.
* @param {Array.<number>} input Input array of coordinate values.
* @param {number=} opt_dimension Dimension (default is 2).
* @return {Array.<number>} Output array of coordinate values.
*/
ol.projection.EPSG3857.fromEPSG4326 = function(point) {
var x = ol.projection.EPSG3857.RADIUS * Math.PI * point.x / 180;
var y = ol.projection.EPSG3857.RADIUS *
Math.log(Math.tan(Math.PI * (point.y + 90) / 360));
return new ol.Coordinate(x, y);
ol.projection.EPSG3857.fromEPSG4326 = function(input, opt_dimension) {
var length = input.length,
dimension = goog.isDef(opt_dimension) ? opt_dimension : 2,
output;
if (dimension > 2) {
// preserve values beyond second dimension
output = input.slice();
} else {
output = new Array(length);
}
goog.asserts.assert(output.length % dimension === 0);
for (var i = 0; i < length; i += dimension) {
output[i] = ol.projection.EPSG3857.RADIUS * Math.PI * input[i] / 180;
output[i + 1] = ol.projection.EPSG3857.RADIUS *
Math.log(Math.tan(Math.PI * (input[i + 1] + 90) / 360));
}
return output;
};
/**
* Transformation from EPSG:3857 to EPSG:4326.
*
* @param {ol.Coordinate} point Point.
* @return {ol.Coordinate} Point.
* @param {Array.<number>} input Input array of coordinate values.
* @param {number=} opt_dimension Dimension (default is 2).
* @return {Array.<number>} Output array of coordinate values.
*/
ol.projection.EPSG3857.toEPSG4326 = function(point) {
var x = 180 * point.x / (ol.projection.EPSG3857.RADIUS * Math.PI);
var y = 360 * Math.atan(
Math.exp(point.y / ol.projection.EPSG3857.RADIUS)) / Math.PI - 90;
return new ol.Coordinate(x, y);
ol.projection.EPSG3857.toEPSG4326 = function(input, opt_dimension) {
var length = input.length,
dimension = goog.isDef(opt_dimension) ? opt_dimension : 2,
output;
if (dimension > 2) {
// preserve values beyond second dimension
output = input.slice();
} else {
output = new Array(length);
}
goog.asserts.assert(output.length % dimension === 0);
for (var i = 0; i < length; i += dimension) {
output[i] = 180 * input[i] / (ol.projection.EPSG3857.RADIUS * Math.PI);
output[i + 1] = 360 * Math.atan(
Math.exp(input[i + 1] / ol.projection.EPSG3857.RADIUS)) / Math.PI - 90;
}
return output;
};