Today we will work with multitouch displays and learn some patterns for how they differ from mouse interactions. Keep in mind that in default form the touch display will mimic a mouse, and sometimes even send events that simulate a mouse wheel if you pinch. You only need to explicitly accommodate touch if you want to handle multiple touches or you hit an edge case where that simulation falls short.
This lecture is going to walk through one d3 example case taken from the d3 docs. Check them out here and here.
If you want to learn a bit more about gestural interactions, $1 gesture recognizers are a decent way to start.