San Francisco Hill Mapper by Samuel M. Maurer

Hill Mapper is an interactive online map of hilly streets in San Francisco. My goal was to show both the steepness of hills and the direction of their incline, using a design that would be more intuitive than topographic contour lines.
The map is intended to help you plan routes that minimize (or maximize!) hills, and also to help you think about the topography of your neighborhood in a novel way. Surprisingly, hills are missing from most maps of San Francisco.