Eh. In D3, just transform the data into X/Y coordinates, create a DIV for each one, and then change the background color based on the desired value. I think it

Eh. In D3, just transform the data into X/Y coordinates, create a DIV for each one, and then change the background color based on the desired value. I think it's d3.scale.color to automatically set up a gradient you plug a value into and get a color out.