Flickr has collected almost ninety million geotagged photos, and for every geotagged photo they have up to six Where On Earth IDs, which are unique numeric identifiers that correspond to the hierarchy of places where a photo was take: the neighborhood, the town, the country, and so on up to the continent in a process called reverse-geocoding.
Eventually they got to thinking: If they plotted all of the geotagged photos associated with a particular WOE ID, would there be enough data to generate a mostly accurate contour of that place?
Apparently the answer is yes, and though it’s not a perfect representation of the place, it’s definitely getting pretty close.
As a gift to the Flickr community, they’ve even made these 150,000 (and counting) WOE IDs with proper (-ish) shape data available via the Flickr API.
It might be a fun toy right now, but give it a few years and add in all of the data from geocoded cell phone photos, and this just might be the future of cartography as we know it.