As the number of smartphone apps that allow you to track your running, biking and other physical activity have surged, so has the amount of data available about how and where people exercise.

Nathan Yau, who runs the blog Flowing Data, used some of that data to create the series of beautiful minimalist maps below. Using data from the app RunKeeper, Yau has mapped the routes people run most often in 20 major cities around the U.S. and the world.

Yau cautions that this data is not complete. It doesn't show all of the running or cycling trips being taken in a city, just those tracked by RunKeeper, and there's also some "noise" in the data -- data recorded in error where, for example, it looks like someone is running on water.

Still, the maps reveal some interesting details. The lines get thicker near bodies of water and on scenic routes, indicating that more people are running that path. Clearly, people prefer to run by the water and in parks, to avoid traffic and enjoy the fresh air and the scenery.

But the maps also give you a sense of how close a city is to scenic routes. In Miami, London and elsewhere, people usually stick to running along the water, whereas in Philadelphia, Chicago and San Francisco, you have far more people running on city streets. In Boise, Charlotte and Minneapolis, you can see that people have fairly easy access to scenic trails nearby.

To see more city maps, check out Yau's site.

Atlanta

Boise

Boston

Charlotte

Chicago

Columbus

Dallas

Washington, D.C.

London

Los Angeles

Miami

Minneapolis

New York

Paris

Philadelphia

San Francisco

Sydney

Tokyo

Toronto

Venice

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