This example shows how to use the util `OGCFilter`, which helps to synchronize
your map layers and feature-grid while using filters on the grid.
The util generates OGC compliant filters that can be attached to WMS or WFS requests in order to filter the map layers content in sync with the grid. Have a look at the `filterchange` listener to see the magic.
The map contains three layers for showcase reasons:
1.) A vectorlayer that is connected with the featuregrid and the map
2.) A WFS vectorlayer which gets filtered through an OGC-Filter which is derived from the utils `buildWfsGetFeatureWithFilter` method
3.) A WMS layer which gets filtered through an OGC-Filter which is derived from the utils `getOGCWMSFilterFromExtJSFilter` method
Have a look at grid-filter.js to see how this is done.