Here's a technique for adding hover/click events to a canvas map. Use a second hidden canvas which has a unique rgb color for each of the regions. Invert the x/

Here's a technique for adding hover/click events to a canvas map. Use a second hidden canvas which has a unique rgb color for each of the regions. Invert the x/y mouse position to lat/lon, lookup the color in the hidden canvas, then lookup the region using that color. You can make the hidden canvas 2x larger than the visible canvas to get good precision on the borders of regions. It's admittedly hacky, but has good performance characteristics since it only uses two canvas elements. http://bl.ocks.org/syntagmatic/6645345 http://bl.ocks.org/syntagmatic/6645345 (hover only activates on mousemove, so the selected region can slide off the cursor)