Time For Action – using addUniqueValueRules

Now that we know about addUniqueValueRules, let's see it in action.

1. We're going to use a basic vector layer with some randomly generated features and settlement_type properties. Add a WMS layer. Then, we need a vector layer:

   vector_layer = new OpenLayers.Layer.Vector('Settlement Vector Layer');
   map.addLayer(vector_layer);

2. Now, let's create an anonymous object consisting of integer values as the keys and our desired settlement_type values as the values. We do this because we'll need a way to randomly pick what type of settlement a feature should be.

   var  settlement_values = { 
       0: 'hut', 
       1: 'village', 
       2: 'city', 
       3: 'metropolis', 
       4: 'facebook' 
   }

3. Ok, let's now create 20 random points. Using code similar to the previous example, we'll create twenty random points and assign a random settlement type to each feature using the settlement_values object we just created.

   for(var i=0; i<20; i++){ 
       vector_layer.addFeatures([new OpenLayers...