Session2-Area1-Canvas.txt

Use canvas to render a ton of data points (20000, 200000 and so on).  With 200000 random rects, canvas still has some latency (less than a second).  SVG will lag a lot more.

Interactivity (hover): can use a hidden canvas to remap mouse points to lat/long, map those to a hidden canvas that has each country in a different share of red (for example), figure out the pixel color, map back to the country and then select it in the main canvas.

Interactivity can also be achieved using d3.quadtree

Interaction is tricky with canvas.  There are some libraries that can also help.  There is no path generator like in svg, but drawing a path in canvas is straightforward.