We covered many examples to get you started with interactivity in your D3 map visualizations. We went over the basics of event handling, explored various methods to bind events to the map, outlined the two d3.behavior APIs, and even dipped our toes into orthographic projections. If you wish to dig deeper into world rotations, and the math involved, check out the Jason Davies article at http://www.jasondavies.com/maps/rotate/.

After two chapters of drawing and interacting with maps, the next chapter will explain how to obtain geo data in order to create any map you want. We'll also include some techniques to optimize the datafiles for viewing the Web.