In this chapter, we'll be developing a web map application that loads in data from a third-party source (Flickr). The examples have been structured with iterative development in mind. What this means is that you start small and make many changes, gradually building up your web map from nothing into something useful. Iterative development is an important, popular, and effective way to develop applications. The core idea is that you create something simple, get it working, and then improve it. You can figure out more quickly what does and doesn't work by improving on, and learning from, the previous iterations.

Another strategy we'll make use of is modular programming. What this means, essentially, is that we try to keep things as discrete (or modular) as possible. By doing so, once we know a component works, we don't have to worry about it later.