Compare City Street Grids One Square Mile at a Time
By Tracy Staedter via Seeker
These maps show at a glance which cities were made for walking and which cities were made for driving.
Anyone who’s ever visited Rome, Paris, Istanbul or Boston knows that part of the charm of these cities is their winding streets, their quaint shops, restaurants and cafes densely packed along narrow roads. Cities would never be laid out like this today.
“It’s one the most fascinating things about city planning,” Geoff Boeing told Seeker. “We explicitly outlaw making the kinds of cities that we all fetishize as tourists.”
Boeing, a PhD candidate at UC Berkeley, is studying urban planning and as part of his research is looking for new ways to characterize street networks, to measure them and to draw some conclusions about how they perform. To that end, he created a data visualization tool that depicts one square mile of a city’s street network and also gives him the ability to compare those squares. At a glance, even a novice “cartophile” can see which cities are best for walking and which cities were made for driving.
Each map is a window into the history of a city’s layout, Boeing said. “It tells us a lot about the design paradigm of when it was built.”
Did it evolve from the bottom up, like Rome or Tunis, and self-organize as the population expanded? Or was it designed from the top down, like Irvine, Calif., to accommodate modern life and the ubiquity of automobiles?
Boeing calls his visualization tool OSMnx — “OSM” stands for OpenStreetMap, a free wiki of maps from around the world, and “nx” stands for NetworkX, which is a computer software package for the creation, manipulation and study of complex networks.
With the tool, Boeing can download any city map in the world and, in addition to analyzing data about physical characteristics of the streets, create the black-and-white grids that show one square mile at a time.
He was inspired to create the data visualization tool after reading the book Great Streets written and illustrated by Allan Jacobs, a Professor of City and Regional Planning also at UC Berkeley. In this book, Jacobs meticulously hand draws 50 one square-mile maps of cities from around the world.
As in Jacobs hand drawings, Boeing’s computer-generated illustrations, the city’s texture is apparent. Compare Portland, founded in 1851, to Irvine, incorporated in 1971. Both are made up of a grid structure with streets mainly at right angles. But the size of those individual grids is obviously different.
Portland’s blocks are small, just 200 feet square. Although the reason behind the size is not known — the Portland Bureau of Transportation says it could have been designed that way to increase the number of highly valued corner lots — the outcome is a highly walkable city. Portland has capitalized on that and back in 1994, it became the first city in the United States to undertake a comprehensive Pedestrian Master Plan.
“It’s very easy to move through that fine-grained mesh and gets to points quickly on foot,” Boeing said.
Irvine tells a different story. “It wasn’t designed for getting anywhere on foot,” he said. “It was designed in the middle to later part of the 20th century for the automobile exclusively.” People don’t walk there.
The car-centric design is a sign of contemporary times that’s still trending. “There are cities in the Middle East or China that are very new that are being built from scratch, and what you tend see is late 20th-century America on steroids.”
It’s a philosophy that could be short-sighted for the future. Self-driving cars and ride-sharing services available through apps like Uber and Lyft could remove a large percentage of vehicles on city streets. Just last week, MIT published a study related to this idea, finding that carpooling could cut the number of taxis in New York City from 14,000 to a mere 3,000.
Although it’s hard to predict how urban planners will design cities to accommodate the evolution of mobility, a data visualization tool like Boeing’s could help people see in an instant how a city could function and help them get closer to what they want from a city.
Will they want a city that’s rational and car-friendly like Irvine? Or will they want a city that’s more pedestrian-oriented like Rome or Paris?
“It helps shift the conversation by demonstrating to people that density isn’t necessarily bad,” Boeing said.
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