Data visualizer and McDonald's heat-mapper Stephen Von Worley has turned his cartographic bag of tricks to the urban street grid. He's released a set of city maps that color-code streets according to how closely they hew to cardinal directions. Predictable street grids (with orderly north-south and east-west layouts) appear in red. The more the roads bend away from this configuration, the more they change color. As you'd expect, the Sunset, Richmond, and Mission districts light up in straitlaced red, and Twin Peaks looks like a total rave.
Von Worley pulled metro-area grids for cities around the globe—London, New York, Paris—from OpenStreetMap and applied an algorithm based on a rainbow color gradient. Streets that take a 30-degree turn look blueish, for instance, and streets that twist around by, say, 60 degrees are green. A 90-degree change goes back to the red family, so a 360-degree turn would spin through the color wheel four times before resetting to red.