Trees, cabs and crime in San Francisco

(Check out the big version!)


I've had this idea to use subtractive blending so that you can see where these three data sets overlap for a while, and decided to scratch the itch this weekend. I'm still not sure if it's significant or even interesting, but here it is. This is a slightly improved version of the original with a more useful (and attractive!) legend and no base map. The colors have also changed: Trees are cyan and crimes magenta because I felt that the latter should stand out more. And yellow combines with magenta to produce red, which seems to me a more crime-y color.


Urban tree locations come courtesy of Friends of the Urban Forest, one day's worth of taxi cab locations from Yellow Cab (via Cabspotting), and a week's worth of reported crime incidents from Crime Reports.


Best, obviously, viewed at original size.

  • Gregor Hochmuth 6y

    This is fantastic! How did you create these? If you programmed this, what framework/language did you use?
  • Julian Burgess 6y

    Very interesting, I've posted about it on the Times Labs Blog.
  • Gadget Boy 6y

    Interesting, what software did you use to achieve this?
  • Shawn Allen 6y

    grex, Gadget Boy: This is actually a screenshot of a Flash piece that's not quite ready for prime time. Modest Maps provides the geographical projection math, and the rest is just 300 lines of hacky ActionScript 3.

    I'd like to make it interactive eventually, but Flash isn't particularly well suited for moving this many points around on the screen (let alone keeping them in memory) at once, so I've resorted to progressively drawing each point to a bitmap rather than addressing them as individual vector objects. I'll probably end up either redoing it in processing or making bitmap tiles of each data layer independently and turning it into a slippy map.

    aubergene: Thanks! FYI, the cab dots are GPS positions of taxis over a 12-hour period (specifically, 8am-8pm on Friday the 13th, 2009). And FUF's data describes meticulously recorded urban tree locations–i.e., planted trees along sidewalks, not (I'm almost certain) naturally occurring trees or those under the care of local and state parks.
  • Ceci Allen 6y

    Amazing - I love your idea. Humm - GPS, could we track our route on Shadowfax?
  • Jérôme Decq 6y

    hmm, aren't there more trees in Golden Gate Park???
  • Shawn Allen 6y

    Jerome: as previously noted, the tree locations are only those recorded by (and, I believe, under the care of) Friends of the Urban Forest. Trees in the city's parks are managed by SF Parks & Rec.
  • brady f 6y

    Nice work as always.
  • alf 6y

    great concept indeed,very good idea the additive cross references
  • Darren Campeau 3y

    I was never the brightest bulb, so can you help me understand how to read this? What can you infer with these overlaps of seemingly random datasets? Criminals take cabs but avoid trees? Victims flee in cabs or climb trees in a pinch?
  • julaville 3y

    at first I thought it said trees, CRABS, and crime... any data on crustacean consumption? I guess we are beyond the real season for it, though.
  • julaville 3y

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Taken on February 15, 2009
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