Refactor projection architecture

2013-02-13 15:33:39 +01:00
parent 9053e1dfc8
commit 6b26cbfb38
9 changed files with 202 additions and 157 deletions
@@ -0,0 +1,23 @@
+goog.provide('ol.projection.addCommonProjections');
+
+goog.require('ol.Projection');
+goog.require('ol.projection.EPSG3857');
+goog.require('ol.projection.EPSG4326');
+
+
+/**
+ * FIXME empty description for jsdoc
+ */
+ol.projection.addCommonProjections = function() {
+  // Add transformations that don't alter coordinates to convert within set of
+  // projections with equal meaning.
+  ol.Projection.addEquivalentProjections(ol.projection.EPSG3857.PROJECTIONS);
+  ol.Projection.addEquivalentProjections(ol.projection.EPSG4326.PROJECTIONS);
+  // Add transformations to convert EPSG:4326 like coordinates to EPSG:3857 like
+  // coordinates and back.
+  ol.Projection.addEquivalentTransforms(
+      ol.projection.EPSG4326.PROJECTIONS,
+      ol.projection.EPSG3857.PROJECTIONS,
+      ol.projection.EPSG3857.fromEPSG4326,
+      ol.projection.EPSG3857.toEPSG4326);
+};
@@ -0,0 +1,97 @@
+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');
+
+
+
+/**
+ * @constructor
+ * @extends {ol.Projection}
+ * @param {string} code Code.
+ */
+ol.projection.EPSG3857 = function(code) {
+  goog.base(
+      this, code, ol.ProjectionUnits.METERS, ol.projection.EPSG3857.EXTENT);
+};
+goog.inherits(ol.projection.EPSG3857, ol.Projection);
+
+
+/**
+ * @const
+ * @type {number}
+ */
+ol.projection.EPSG3857.RADIUS = 6378137;
+
+
+/**
+ * @const
+ * @type {number}
+ */
+ol.projection.EPSG3857.HALF_SIZE = Math.PI * ol.projection.EPSG3857.RADIUS;
+
+
+/**
+ * @const
+ * @type {ol.Extent}
+ */
+ol.projection.EPSG3857.EXTENT = new ol.Extent(
+    -ol.projection.EPSG3857.HALF_SIZE, -ol.projection.EPSG3857.HALF_SIZE,
+    ol.projection.EPSG3857.HALF_SIZE, ol.projection.EPSG3857.HALF_SIZE);
+
+
+/**
+ * Lists several projection codes with the same meaning as EPSG:3857.
+ *
+ * @type {Array.<string>}
+ */
+ol.projection.EPSG3857.CODES = [
+  'EPSG:3857',
+  'EPSG:102100',
+  'EPSG:102113',
+  'EPSG:900913'
+];
+
+
+/**
+ * Projections equal to EPSG:3857.
+ *
+ * @const
+ * @type {Array.<ol.Projection>}
+ */
+ol.projection.EPSG3857.PROJECTIONS = goog.array.map(
+    ol.projection.EPSG3857.CODES,
+    function(code) {
+      return new ol.projection.EPSG3857(code);
+    });
+
+
+/**
+ * Transformation from EPSG:4326 to EPSG:3857.
+ *
+ * @param {ol.Coordinate} point Point.
+ * @return {ol.Coordinate} Point.
+ */
+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);
+};
+
+
+/**
+ * Transformation from EPSG:3857 to EPSG:4326.
+ *
+ * @param {ol.Coordinate} point Point.
+ * @return {ol.Coordinate} Point.
+ */
+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);
+};
@@ -0,0 +1,42 @@
+goog.provide('ol.projection.EPSG4326');
+
+goog.require('ol.Extent');
+goog.require('ol.Projection');
+goog.require('ol.ProjectionUnits');
+
+
+
+/**
+ * @constructor
+ * @extends {ol.Projection}
+ * @param {string} code Code.
+ * @param {string=} opt_axisOrientation Axis orientation.
+ */
+ol.projection.EPSG4326 = function(code, opt_axisOrientation) {
+  goog.base(this, code, ol.ProjectionUnits.DEGREES,
+      ol.projection.EPSG4326.EXTENT, opt_axisOrientation);
+};
+goog.inherits(ol.projection.EPSG4326, ol.Projection);
+
+
+/**
+ * Extent of the EPSG:4326 projection which is the whole world.
+ *
+ * @const
+ * @type {ol.Extent}
+ */
+ol.projection.EPSG4326.EXTENT = new ol.Extent(-180, -90, 180, 90);
+
+
+/**
+ * Projections equal to EPSG:4326.
+ *
+ * @const
+ * @type {Array.<ol.Projection>}
+ */
+ol.projection.EPSG4326.PROJECTIONS = [
+  new ol.projection.EPSG4326('CRS:84'),
+  new ol.projection.EPSG4326('EPSG:4326', 'neu'),
+  new ol.projection.EPSG4326('urn:ogc:def:crs:EPSG:6.6:4326', 'neu'),
+  new ol.projection.EPSG4326('urn:ogc:def:crs:OGC:1.3:CRS84')
+];