docs: function(feature) {
          var intersect = false;
          switch(this.type) {
              case OpenLayers.Filter.Spatial.BBOX:
              case OpenLayers.Filter.Spatial.INTERSECTS:
                  if(feature.geometry) {
                      var geom = this.value;
                      if(this.value.CLASS_NAME == "OpenLayers.Bounds") {
                          geom = this.value.toGeometry();
                      }
                      if(feature.geometry.intersects(geom)) {
                          intersect = true;
                      }
                  }
                  break;
              default:
                  throw new Error('evaluate is not implemented for this filter type.');
          }
          return intersect;
      }