Add fromLonLat and toLonLat convenience functions

examples/animation.js

@@ -34,12 +34,12 @@ function elastic(t) {
   return Math.pow(2, -10 * t) * Math.sin((t - 0.075) * (2 * Math.PI) / 0.3) + 1;
 }
 
-var london = ol.proj.transform([-0.12755, 51.507222], 'EPSG:4326', 'EPSG:3857');
+var london = ol.proj.fromLonLat([-0.12755, 51.507222]);
-var moscow = ol.proj.transform([37.6178, 55.7517], 'EPSG:4326', 'EPSG:3857');
+var moscow = ol.proj.fromLonLat([37.6178, 55.7517]);
-var istanbul = ol.proj.transform([28.9744, 41.0128], 'EPSG:4326', 'EPSG:3857');
+var istanbul = ol.proj.fromLonLat([28.9744, 41.0128]);
-var rome = ol.proj.transform([12.5, 41.9], 'EPSG:4326', 'EPSG:3857');
+var rome = ol.proj.fromLonLat([12.5, 41.9]);
-var bern = ol.proj.transform([7.4458, 46.95], 'EPSG:4326', 'EPSG:3857');
+var bern = ol.proj.fromLonLat([7.4458, 46.95]);
-var madrid = ol.proj.transform([-3.683333, 40.4], 'EPSG:4326', 'EPSG:3857');
+var madrid = ol.proj.fromLonLat([-3.683333, 40.4]);
 
 var view = new ol.View({
   // the view's initial state

examples/d3.js

@@ -21,7 +21,7 @@ var map = new ol.Map({
   ],
   target: 'map',
   view: new ol.View({
-    center: ol.proj.transform([-97, 38], 'EPSG:4326', 'EPSG:3857'),
+    center: ol.proj.fromLonLat([-97, 38]),
     zoom: 4
   })
 });

examples/geolocation-orientation.js

@@ -10,7 +10,7 @@ goog.require('ol.source.OSM');
 
 // creating the view
 var view = new ol.View({
-  center: ol.proj.transform([5.8713, 45.6452], 'EPSG:4326', 'EPSG:3857'),
+  center: ol.proj.fromLonLat([5.8713, 45.6452]),
   zoom: 19
 });
 

examples/graticule.js

@@ -16,7 +16,7 @@ var map = new ol.Map({
   renderer: 'canvas',
   target: 'map',
   view: new ol.View({
-    center: ol.proj.transform([4.8, 47.75], 'EPSG:4326', 'EPSG:3857'),
+    center: ol.proj.fromLonLat([4.8, 47.75]),
     zoom: 5
   })
 });

examples/hue-saturation.js

@@ -34,7 +34,7 @@ if (!ol.has.WEBGL) {
     renderer: 'webgl',
     target: 'map',
     view: new ol.View({
-      center: ol.proj.transform([-9.375, 51.483333], 'EPSG:4326', 'EPSG:3857'),
+      center: ol.proj.fromLonLat([-9.375, 51.483333]),
       zoom: 15
     })
   });

examples/image-filter.js

@@ -14,7 +14,7 @@ var map = new ol.Map({
   layers: [imagery],
   target: 'map',
   view: new ol.View({
-    center: ol.proj.transform([-120, 50], 'EPSG:4326', 'EPSG:3857'),
+    center: ol.proj.fromLonLat([-120, 50]),
     zoom: 6
   })
 });

examples/layer-group.js

@@ -33,7 +33,7 @@ var map = new ol.Map({
   renderer: exampleNS.getRendererFromQueryString(),
   target: 'map',
   view: new ol.View({
-    center: ol.proj.transform([37.40570, 8.81566], 'EPSG:4326', 'EPSG:3857'),
+    center: ol.proj.fromLonLat([37.40570, 8.81566]),
     zoom: 4
   })
 });

examples/layer-spy.js

@@ -18,7 +18,7 @@ var map = new ol.Map({
   layers: [roads, imagery],
   target: 'map',
   view: new ol.View({
-    center: ol.proj.transform([-109, 46.5], 'EPSG:4326', 'EPSG:3857'),
+    center: ol.proj.fromLonLat([-109, 46.5]),
     zoom: 6
   })
 });

examples/overlay.js

@@ -21,7 +21,7 @@ var map = new ol.Map({
   })
 });
 
-var pos = ol.proj.transform([16.3725, 48.208889], 'EPSG:4326', 'EPSG:3857');
+var pos = ol.proj.fromLonLat([16.3725, 48.208889]);
 
 // Vienna marker
 var marker = new ol.Overlay({

examples/semi-transparent-layer.js

@@ -21,7 +21,7 @@ var map = new ol.Map({
   renderer: exampleNS.getRendererFromQueryString(),
   target: 'map',
   view: new ol.View({
-    center: ol.proj.transform([-77.93255, 37.9555], 'EPSG:4326', 'EPSG:3857'),
+    center: ol.proj.fromLonLat([-77.93255, 37.9555]),
     zoom: 5
   })
 });

examples/tile-vector.js

@@ -152,7 +152,7 @@ var map = new ol.Map({
   renderer: 'canvas',
   target: document.getElementById('map'),
   view: new ol.View({
-    center: ol.proj.transform([-74.0064, 40.7142], 'EPSG:4326', 'EPSG:3857'),
+    center: ol.proj.fromLonLat([-74.0064, 40.7142]),
     maxZoom: 19,
     zoom: 15
   })

examples/wms-image-custom-proj.js

@@ -75,7 +75,7 @@ var map = new ol.Map({
   target: 'map',
   view: new ol.View({
     projection: projection,
-    center: ol.proj.transform([8.23, 46.86], 'EPSG:4326', projection),
+    center: ol.proj.fromLonLat([8.23, 46.86], projection),
     extent: extent,
     zoom: 2
   })

examples/xyz-esri.js

@@ -23,7 +23,7 @@ var map = new ol.Map({
     })
   ],
   view: new ol.View({
-    center: ol.proj.transform([-121.1, 47.5], 'EPSG:4326', 'EPSG:3857'),
+    center: ol.proj.fromLonLat([-121.1, 47.5]),
     zoom: 7
   })
 });

src/ol/proj/proj.js

@@ -586,6 +586,36 @@ ol.proj.removeTransform = function(source, destination) {
 };
 
 
+/**
+ * Transforms a coordinate from longitude/latitude to a different projection.
+ * @param {ol.Coordinate} coordinate Coordinate as longitude and latitude, i.e.
+ *     an array with longitude as 1st and latitude as 2nd element.
+ * @param {ol.proj.ProjectionLike=} opt_projection Target projection. The
+ *     default is Web Mercator, i.e. 'EPSG:3857'.
+ * @return {ol.Coordinate} Coordinate projected to the target projection.
+ * @api stable
+ */
+ol.proj.fromLonLat = function(coordinate, opt_projection) {
+  return ol.proj.transform(coordinate, 'EPSG:4326',
+      goog.isDef(opt_projection) ? opt_projection : 'EPSG:3857');
+};
+
+
+/**
+ * Transforms a coordinate to longitude/latitude.
+ * @param {ol.Coordinate} coordinate Projected coordinate.
+ * @param {ol.proj.ProjectionLike=} opt_projection Projection of the coordinate.
+ *     The default is Web Mercator, i.e. 'EPSG:3857'.
+ * @return {ol.Coordinate} Coordinate as longitude and latitude, i.e. an array
+ *     with longitude as 1st and latitude as 2nd element.
+ * @api stable
+ */
+ol.proj.toLonLat = function(coordinate, opt_projection) {
+  return ol.proj.transform(coordinate,
+      goog.isDef(opt_projection) ? opt_projection : 'EPSG:3857', 'EPSG:4326');
+};
+
+
 /**
  * Fetches a Projection object for the code specified.
  *

test/spec/ol/proj/proj.test.js

@@ -78,7 +78,7 @@ describe('ol.proj', function() {
   describe('transform from 4326 to 3857 (Alastaira)', function() {
     // http://alastaira.wordpress.com/2011/01/23/the-google-maps-bing-maps-spherical-mercator-projection/
 
-    it('returns expected value', function() {
+    it('returns expected value using ol.proj.transform', function() {
       var point = ol.proj.transform(
           [-5.625, 52.4827802220782], 'EPSG:4326', 'EPSG:900913');
       expect(point).not.to.be(undefined);
@@ -86,12 +86,20 @@ describe('ol.proj', function() {
       expect(point[0]).to.roughlyEqual(-626172.13571216376, 1e-9);
       expect(point[1]).to.roughlyEqual(6887893.4928337997, 1e-8);
     });
+
+    it('returns expected value using ol.proj.fromLonLat', function() {
+      var point = ol.proj.fromLonLat([-5.625, 52.4827802220782]);
+      expect(point).not.to.be(undefined);
+      expect(point).not.to.be(null);
+      expect(point[0]).to.roughlyEqual(-626172.13571216376, 1e-9);
+      expect(point[1]).to.roughlyEqual(6887893.4928337997, 1e-8);
+    });
   });
 
   describe('transform from 3857 to 4326 (Alastaira)', function() {
     // http://alastaira.wordpress.com/2011/01/23/the-google-maps-bing-maps-spherical-mercator-projection/
 
-    it('returns expected value', function() {
+    it('returns expected value using ol.proj.transform', function() {
       var point = ol.proj.transform([-626172.13571216376, 6887893.4928337997],
           'EPSG:900913', 'EPSG:4326');
       expect(point).not.to.be(undefined);
@@ -99,6 +107,14 @@ describe('ol.proj', function() {
       expect(point[0]).to.roughlyEqual(-5.625, 1e-9);
       expect(point[1]).to.roughlyEqual(52.4827802220782, 1e-9);
     });
+
+    it('returns expected value using ol.proj.toLonLat', function() {
+      var point = ol.proj.toLonLat([-626172.13571216376, 6887893.4928337997]);
+      expect(point).not.to.be(undefined);
+      expect(point).not.to.be(null);
+      expect(point[0]).to.roughlyEqual(-5.625, 1e-9);
+      expect(point[1]).to.roughlyEqual(52.4827802220782, 1e-9);
+    });
   });
 
   describe('transformExtent()', function() {
@@ -139,6 +155,21 @@ describe('ol.proj', function() {
       delete proj4.defs['EPSG:21781'];
     });
 
+    it('works with ol.proj.fromLonLat and ol.proj.toLonLat', function() {
+      proj4.defs('EPSG:21781',
+          '+proj=somerc +lat_0=46.95240555555556 +lon_0=7.439583333333333 ' +
+          '+k_0=1 +x_0=600000 +y_0=200000 +ellps=bessel ' +
+          '+towgs84=674.374,15.056,405.346,0,0,0,0 +units=m +no_defs');
+      var lonLat = [7.439583333333333, 46.95240555555556];
+      var point = ol.proj.fromLonLat(lonLat, 'EPSG:21781');
+      expect(point[0]).to.roughlyEqual(600072.300, 1);
+      expect(point[1]).to.roughlyEqual(200146.976, 1);
+      point = ol.proj.toLonLat(point, 'EPSG:21781');
+      expect(point[0]).to.roughlyEqual(lonLat[0], 1);
+      expect(point[1]).to.roughlyEqual(lonLat[1], 1);
+      delete proj4.defs['EPSG:21781'];
+    });
+
     it('caches the new Proj4js projections given their srsCode', function() {
       proj4.defs('EPSG:21781',
           '+proj=somerc +lat_0=46.95240555555556 +lon_0=7.439583333333333 ' +