An intern at Facebook named Paul Butler was interested in what he calls “the locality of friendship”; he wanted a visualization that would show which cities had a lot of friendships between them.  He sampled about ten million pairs of friends, combing that data “with each user’s current city and summed the number of friends between each pair of cities.  Then [he] merged the data with the longitude and latitude of each city.”  The image above is the result, and this was his initial reaction:

The blob had turned into a surprisingly detailed map of the world. Not only were continents visible, certain international borders were apparent as well. What really struck me, though, was knowing that the lines didn’t represent coasts or rivers or political borders, but real human relationships.

Pretty incredible, huh?  Just by combining data points between friend connections on Facebook he was able to recreate a unique map of the world (though Russia and China are almost totally absent).  The white areas on the “map” represent cities and towns, while the blue streaks highlight the relationships between them.  If you’re interested in learning more about how this was constructed, head over to Butler’s blog post; there you’ll also find a super hi-res version of the visualization.  FYI, it makes for a visually splendid desktop background.

[Via Facebook]