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Visualizing Exactly How Subways Distort Our Sense of Space

An experiment from Shanghai.

By definition, subways are geographically disorienting. While we move through them, we can't see where we're going – or, rather, where we are relative to the landmarks above. Our sense of speed (and therefore distance) is disarmed by the fact that there's not much to watch out the window. And then there are the maps, network diagrams that are intentionally distorted to simplify information at the expense of geography.

"Riding an underground train robs us from using visual references of the city," emails Till Nagel, a research associate at the Interaction Design Lab in Potsdam, Germany. So how do subways change the way we perceive geography above ground?

To play with this question, Nagel and Benedikt Groß created a clever animation of the Shanghai metro system, one of the busiest in the world with more than 8 million rides a day. This is an actual map of the region, with the subway network accurately overlaid on top of it:

And this is what the streamlined Shanghai subway map looks like:

In the below video, Nagel and Groß animated the system over a typical day, using timetable data from the Shanghai Metro website to create the effect of a pulsing network (the agency doesn't publish real-time data). They start with a geographically accurate map of the region, but then the animation morphs into the schematic view you see above:


Shanghai Metro Flow from Till Nagel on Vimeo.

Decades ago, Harry Beck's iconic map of the London Underground set the standard for how we visualize subway systems. Writes Till:

But do we understand that different areas of the city are differently shown? Do we realize the city center is under some kind of fisheye lens? And does this change the way we see our city? 

Of course, most of us do not navigate through the city with a perfect mental map anyway, but use landmarks and/or have only rough estimations of distances. Many factors influence our perception of a city: from how the speed of travel affects which details we can observe, to how senses such as smell affect our memory of a place. 

With our work, we wanted to illustrate the distortions of Shanghai's metro network, and question if and how strongly such schematic subway maps affect our understanding of the city.

If you've never been to Shanghai, this particular exercise may not be as eye-opening for you. But here is another great project from Northeastern University's Benjamin M. Schmidt that similarly plays with our perceptions of space in the Boston, Washington and New York subways (hat tip to Gizmodo).

The differences between transit diagrams and actual geography are never more apparent than when we layer the two on top of each other. The result raises fascinating questions not just about how we perceive geography from the darkened subway, but also how ubiquitous subway maps influence the way we imagine the city above ground. When you're heading out of a bar tonight for the nearest train, which map will you picture in your head: The familiar subway diagram, or some more intricate and accurate street grid?

About the Author

  • Emily Badger is a former staff writer at CityLab. Her work has previously appeared in Pacific StandardGOODThe Christian Science Monitor, and The New York Times. She lives in the Washington, D.C. area.