Add synthetic data example

examples/synthetic-data.js

@@ -0,0 +1,69 @@
+goog.require('goog.functions');
+goog.require('ol.Map');
+goog.require('ol.Overlay');
+goog.require('ol.RendererHint');
+goog.require('ol.View2D');
+goog.require('ol.format.GeoJSON');
+goog.require('ol.layer.Vector');
+goog.require('ol.source.Vector');
+goog.require('ol.symbol');
+
+
+// build up some GeoJSON features
+var count = 20000;
+var features = new Array(count);
+var e = 18000000;
+for (var i = 0; i < count; ++i) {
+  features[i] = {
+    type: 'Feature',
+    properties: {
+      i: i,
+      size: i % 2 ? 10 : 20
+    },
+    geometry: {
+      type: 'Point',
+      coordinates: [
+        2 * e * Math.random() - e, 2 * e * Math.random() - e
+      ]
+    }
+  };
+}
+
+var vectorSource = new ol.source.Vector();
+new ol.format.GeoJSON().readObject({
+  type: 'FeatureCollection',
+  features: features
+}, vectorSource.addFeature, vectorSource);
+
+var styleFunction = goog.functions.constant({
+  image: ol.symbol.renderCircle(
+      5,
+      {
+        color: '#666666'
+      },
+      {
+        color: '#bada55',
+        width: 1
+      })
+});
+
+
+var vector = new ol.layer.Vector({
+  source: vectorSource,
+  styleFunction: styleFunction
+});
+
+var popup = new ol.Overlay({
+  element: document.getElementById('popup')
+});
+
+var map = new ol.Map({
+  layers: [vector],
+  renderer: ol.RendererHint.CANVAS,
+  target: 'map',
+  view: new ol.View2D({
+    center: [0, 0],
+    zoom: 2
+  }),
+  overlays: [popup]
+});