The Buses and Trains of San Francisco – Visualized

As part of our work on the SPUR opening exhibition, we wrote some code sketches using some live NextBus data (thanks NextBus!), who gave us the GPS coordinates of all the buses and trains in the San Francisco public transit system, MUNI.  We goofed around with an interactive 3D visualization – the white cubes are buses or trains – that was fun. These videos are played back faster than real time – sadly our public transit vehicles don’t travel this fast.

We also built a 2D visualization with a tracing effect.  In both sketches, it’s fun to note how you can see the main streets and arteries of the city traced out by the movement of the vehicles – Market Street is prominent as it cuts its diagonal through the eastern half of the city, and we can see the fast buses zipping across the Bay Bridge to and from Treasure Island in the Bay. You can also see the Golden Gate Bridge and Presidio sparsely outlined in the upper left.

One interesting outcome – in the 2D visualization, there’s a point at which all the buses seem to start floating away, leaving the grid of the city and clustering in strange locations.  We thought this was a bug at first, but really it’s an outcome of the data.  At the end of the day, the buses seem to turn off the GPS as they return home.  We simply interpolate their positions as they float back to (what we think are) their depots.  And when they day starts anew, they quickly being zooming about, retracing the grid of the city as the morning commute begins.