Compare City Street Grids One Square Mile at a Time
By Tracy Staedter
9 January 2017
Photo courtesy Geoff Boeing
Anyone who’s visited Rome, Paris, Istanbul or Boston knows that part of the charm of these cities is their winding streets, quaint shops, and lively restaurants and cafes. Cities would never be laid out like this today.
"It's one the most fascinating things about city planning," said Geoff Boeing, a PhD candidate in City & Regional Planning at the College of Environmental Design. "We explicitly outlaw making the kinds of cities that we all fetishize as tourists."
Boeing is studying urban planning, and part of his research is looking for new ways to characterize street networks, measure them and draw some conclusions about how they perform. He has 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."
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 Professor Emeritus of City & Regional Planning Allan Jacobs. In his 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 make the city's texture apparent: Compare Portland, founded in 1851, to Irvine, incorporated in 1971, and see that 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: 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 explained. Irvine, on the other hand, 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."
A sign of contemporary times, car-centric design is still trending in much of the world. "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."
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 prefer 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.