We covered many examples to get you started with interactivity for your D3 map visualizations. We went over the basics of event handling, explored various methods to bind events to the map, outlined the two behavior APIs d3.zoom() and d3.drag(), 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 data files for viewing the web.
