German Döner, English Curry & American Pizza

German Döner Kebab restaurants have started popping up all over London. For some reason, the idea of a German kebab still strikes me as slightly incongruous - a bit like a Swiss curry or a French taco. However, according to a recent analysis of OpenStreetMap food venues, there are far more döner kebab restaurants in Germany than there are in Turkey. In fact, 51% of the world's döner shops are located in Germany.

The surprising truth is that restaurant names often tell us more about migration and language than they do about the birthplace of a dish. That's the premise behind Flavor Lines, an ingenious interactive map that uses millions of restaurant names from OpenStreetMap to reveal the invisible cultural boundaries that shape the world's cuisine.

Rather than mapping where people eat particular foods, Flavor Lines maps where those foods become part of a restaurant's identity. The application searches OpenStreetMap restaurant names for dishes ranging from döner and shawarma to plov, biryani, pierogi and pelmeni. Every location on the map is then coloured according to the nearest restaurant bearing that dish's name, creating striking territories where one culinary term gives way to another.

The resulting boundaries resemble linguistic isoglosses more than political borders. One of the most striking examples is the transition from plov to biryani around the Hindu Kush, while across Eastern Europe pierogi gradually give way to varenyky and then pelmeni as languages change. These aren't borders imposed by geography so much as by culture.

The real achievement of Flavor Lines is that it demonstrates how much hidden information exists within OpenStreetMap. By looking not at where restaurants are located, but at what they choose to call themselves, the map uncovers patterns of migration, language and identity that might otherwise remain invisible.