Web maps are very popular today, and are growing in popularity. After Google Maps was introduced, there was an explosion of interactive web maps. Google provides an API to interact with its mapping service, as others do now, and OpenLayers works well with most of them. Not only can we use these third-party APIs with OpenLayers, we can also mash up other layers on top of them. Those services are the most popular, but they suffer from bottleneck depending on your web mapping application. So, you need to know mainstream API and alternatives to display raster images.
In this chapter, we will learn the following: