Before getting started
In the previous chapter, we finalized our sample WebGIS application. That's it; we won't extend it anymore in this chapter or in future chapters. As we later need to create some controls for different operations, we go back to our layer tree model from Chapter 3, Working with Layers. We will use the ch03_layerorder example as our starting point and customize it later according to our needs.
We will not use any third-party library in this chapter; however, we need a large dataset so that we can try out the capabilities of the WebGL renderer. This dataset can be located in the res folder. It's name is switzerland_points_osm.geojson, and it contains 221,291 point features from the OpenStreetMap database.
