Today’s map comes from Dustin Cable, from the Demographics Research Group at the University of Virginia. The map, much like the New York Times’ lauded census maps, visualizes race distribution in census blocks, based on the 2010 American census. Each dot corresponds to one person, and is colour-coded to correspond to race. Just as with pointilist paintings, having a variety of colours placed together produces the illusion of a different colour, and sparseness of points creates the sense of a lighter hue.
The developers go into detail about the construction of the map here. The map was constructed using python, SAS, Processing and Google Maps API.