@richard – yes, there is some smoothing in effect, which means that the ridge along Shotwell St (for the prostitution map) is indeed a bit smoothed between peaks. That’s not to say that there are only two peaks at Shotwell and 19th and Shotwell and 17th. There are incidents in between as well, but the big peaks at those major intersections does mean that the ridge between them appears higher than the actual incidents along those blocks support.
A lot of people have commented on the usefulness of maps like these. I want to stress once again: this was done as an art project much more than a useful visualization. My goal was not to provide useful information that one could act on.