The Visual Signature of Your City

Social-media platforms like FourSquare and Twitter have been a boon for sociologists and geographers who now have entirely new ways of tracking how we move through cities, where we go, who we are, and even what we think of the world around us. There is one set of social-media platforms, however, that has been tougher to crack for useful data than others: photo-sharing sites.

Their metadata can illustrate where people take photos, and how active they are. In at least one case, researchers have also been able to break down the architectural details contained in photos of urban streetscapes. But on the whole, how do you aggregate useful data about entire cities and the differences between them from the content of millions of photos on a site like Instagram?