Because OpenLayers is so flexible, it's easy to make third party software and data work with our maps. Sharing geospatial data is becoming more popular, with services such as Flickr and Twitter freely offering geospatially embedded data. Being able to visualize data often helps us to understand it. Using OpenLayers, we can place geospatial data (say, twitter posts or Flickr images) on a map and get a clearer picture about the data.
Many popular sites provide an API (Application Programmer Interface) which allows programmers to interact with their data. For instance, both Flickr and Twitter provide APIs that enables developers to view recent updates (photo uploads and tweets). These APIs (but not all APIs) let us get geospatial data that we can use with OpenLayers. Flickr provides some very easy to use methods to retrieve data with associated geographic information, so we'll focus this chapter on building a web-mapping application around...