We've looked at some small-scale uses of OpenStreetMap data covering a single village. This is fine up to a point, but you need larger amounts of data than this for any reasonably serious application. There are many ways of getting at the raw data in the OpenStreetMap database, depending on how much you want, how often you want it, and how much processing you're prepared to do yourself. The main methods are:
Planet files
The main OpenStreetMap API
The Extended API (XAPI)
Each of these provides data in a different way, each with advantages and disadvantages. We'll discuss these in this chapter, and you should get an idea of which method will suit your application best.
As all of these methods provide data using Extensible Markup Language (XML), it will help you understand some of the examples given if you have a basic understanding of XML, but it is possible to retrieve, process, and use OpenStreetMap data without ever seeing a single line of XML, provided...