A couple of blogs today (GGW, DCist) featured this fantastic map of DC and environs from Flickr user Eric Fischer.

Fischer has a set of similar maps from various cities around the world.  Fischer’s methodology takes data from the images and the user accounts to determine the location of the photo (via geotagging), as well as the time and date and the type of user (tourist, local, or unknown).  Tourist photos are in red, locals in blue, and unknown data in yellow.  Each dot represents a photo.  Photos taken in succession by the same user within 10 minutes of each other are connected by a line.

Fischer also has maps of cities that do not discern between tourists and locals.