Most of us want to believe that our cities are unique, special snowflakes, unlike anywhere else in the world. But a new study analyzing 131 different city grids has found that every city falls into one of four categories. Staten Island, for example, has a lot in common with the Syrian city of As-Suwayda.
The study is titled A typology of street patterns, and in it, authors Rémi Louf and Marc Barthelemy explain how a complex mathematical analysis of each city's block shape, size, and layout was used to define four discrete city types:
- First, there's a familiar fingerprint made up of medium-sized blocks, laid out orthogonally.
- Second, a more fractured system of blocks of all sorts of shapes.
- Third, another medium-sized block fingerprint, but with more shapes than simple squares or rectangles.
- Finally, the fourth fingerprint is a "mosaic" of smaller areas filled with rectangular blocks.
How does this analysis differ from the way city grids have traditionally been studied? For starters, rather than look simply at the street grid, the authors focused on the "shape factor" of the blocks themselves, creating what they describe as a "fingerprint" for each city. You can think of it as reading the positive space (the blocks) rather than the negative space (the streets). For example, check out this image. It shows every single block in Montreal, arranged on the y-axis by size and by regularity on the x-axis:
But what's even more interesting than the four groups themselves are the ways the analysis methodology let the authors compare wildly disparate cities. On QuantUrb, the research team looks at each individual borough of New York City—each with its own grid system—and shows what global cities they're most similar to. Take Manhattan: Though we think of it as the prototypical grid, it's actually pretty irregular—especially when you get into lower Manhattan. That's why it's closest to two Brazilian cities: Campo Grande and Curitiba.
Meanwhile, Brooklyn is more like the standardized layouts of Detroit and Brussels. Queens is also a lot like Detroit, as well as Miami. The Bronx is like Porto, Portugal. Perhaps the biggest surprise, though, is Staten Island: The researchers say it's a lot like As-Suwayda, Syria:
Your city might be special to you—but nearly all of our cities share some basic attributes. Though the paper itself is behind the paywall of Journal of the Royal Society Interface, you can get a more information from Science Mag and Discovery. [ScienceMag; QuantUrb; Discovery; Journal of the Royal Society Interface]
Lead image: Sean Pavone