New example showing how to switch projections

2013-04-18 16:54:37 +02:00
parent 80a6185947
commit 010035e047
2 changed files with 125 additions and 0 deletions
--- a/examples/polar-projections.js
+++ b/examples/polar-projections.js
@@ -0,0 +1,84 @@
+var map, layer, overlay;
+
+var projectionOptions = {
+    'EPSG:3574': {
+        projection: new OpenLayers.Projection('EPSG:3574'),
+        units: 'm',
+        maxExtent: new OpenLayers.Bounds(-5505054, -5505054, 5505054, 5505054),
+        maxResolution: 5505054 / 128,
+        numZoomLevels: 18
+    },
+    'EPSG:3576': {
+        projection: new OpenLayers.Projection('EPSG:3576'),
+        units: 'm',
+        maxExtent: new OpenLayers.Bounds(-5505054, -5505054, 5505054, 5505054),
+        maxResolution: 5505054 / 128,
+        numZoomLevels: 18
+    },
+    'EPSG:3571': {
+        projection: new OpenLayers.Projection('EPSG:3571'),
+        units: 'm',
+        maxExtent: new OpenLayers.Bounds(-5505054, -5505054, 5505054, 5505054),
+        maxResolution: 5505054 / 128,
+        numZoomLevels: 18
+    },
+    'EPSG:3573': {
+        projection: new OpenLayers.Projection('EPSG:3573'),
+        units: 'm',
+        maxExtent: new OpenLayers.Bounds(-5505054, -5505054, 5505054, 5505054),
+        maxResolution: 5505054 / 128,
+        numZoomLevels: 18
+    }
+};
+
+function setProjection() {
+    projCode = this.innerHTML;
+    var oldExtent = map.getExtent();
+    var oldCenter = map.getCenter();
+    var oldProjection = map.getProjectionObject();
+    
+    // map projection is controlled by the base layer
+    map.baseLayer.addOptions(projectionOptions[projCode]);
+    
+    // with the base layer updated, the map has the new projection now
+    var newProjection = map.getProjectionObject();
+    
+    // transform the center of the old projection, not the extent
+    map.setCenter(
+        oldCenter.transform(oldProjection, newProjection,
+        map.getZoomForExtent(oldExtent.transform(oldProjection, newProjection))
+    ));
+    
+    for (var i=map.layers.length-1; i>=0; --i) {
+        // update grid settings
+        map.layers[i].addOptions(projectionOptions[projCode]);
+        // redraw layer - just in case center and zoom are the same in old and
+        // new projection
+        map.layers[i].redraw();
+    }
+}
+
+function init() {
+    map = new OpenLayers.Map('map');
+    layer = new OpenLayers.Layer.WMS(
+        'world',
+        'http://v2.suite.opengeo.org/geoserver/wms',
+        {layers: 'world', version: '1.1.1'},
+        projectionOptions['EPSG:3574']
+    );
+    overlay = new OpenLayers.Layer.WMS(
+        'world',
+        'http://v2.suite.opengeo.org/geoserver/wms',
+        {transparent: 'true', layers: 'world:borders', styles: 'line'},
+        projectionOptions['EPSG:3574']
+    );
+    overlay.isBaseLayer = false;
+    map.addLayers([layer, overlay]);
+    map.zoomToMaxExtent();
+    
+    // add behaviour to dom elements
+    document.getElementById('epsg3574').onclick = setProjection;
+    document.getElementById('epsg3576').onclick = setProjection;
+    document.getElementById('epsg3571').onclick = setProjection;
+    document.getElementById('epsg3573').onclick = setProjection;
+}