Every geotagged photo on Flickr has up to six Where On Earth (WOE) IDs associated with it. These are unique numeric identifiers that correspond to the hierarchy of places where a photo was taken: the neighbourhood, the town, the county, and so on up to continents.

If all the location data for a given WOE ID were plotted on a map could you generate a mostly accurate shape of that place?

— Aaron Straup Cope, Flickr Shapetiles