OpenLayers is a big and complex framework. Advantageously, such a powerful and mature framework allows us to work with many GIS standards, read from many different data sources, render on different browser technologies, and so on. This capability does come at a cost, complexity, and download size to name a few.
As when learning anything else, spending time with OpenLayers will result in a familiarization of the library concepts, and we'll look at how to reduce download size in the Using the custom OpenLayers library build recipe, which is especially useful for mobile users or situations where network limitations may be unavoidable.
The implementation of OpenLayers 3 has less homegrown utility functionality, as seen in OpenLayers 2. OpenLayers 3 leans on the Google Closure library for this reason. With Google Closure embedded in the library core, OpenLayers is theoretically a self-contained library with no other dependencies required.
In this chapter, we'll take a look at some more...