Elegant Graphs Reduce 25 American Cities to Their Design Essence
By Henry Grabar
July 11, 2018
Photos courtesy Geoff Boeing
Geoff Boeing (Ph.D. City & Regional Planning ‘17), a College of Environmental Design alumnus and postdoc in the Urban Analytics Lab at UC Berkeley, has found a way to visually represent a city in a a clever, shorthand way.
By downloading and crunching municipal boundaries and street networks from OpenStreetMap, Boeing has assembled histograms that show the distribution of the orientations of a city’s streets, but visualized around the points of a compass.
Consider the exceptionally gridded terrain of Tampa, Florida, where nearly every street runs north-south or east-west. As a histogram, it’s a perfect compass. A city where separate grids connect, like St. Louis, looks a little noisier. Among Boeing’s conclusions? It’s Charlotte, North Carolina—that sprawling Sun Belt metropolis not known for its charming, cozy urban spaces—that most closely resembles the tangled street grids of Paris or London.
A handful of Boeing’s histograms serve as shorthands for urban history—in Detroit, for example, a compass-rose-style histogram shows how the city’s initial orientation towards its riverfront gave way to the north-south Jeffersonian grid. This is even true in postwar cities riddled with suburban cul-de-sacs. “In places like Orlando and Phoenix, once you get inside of the gridded superblocks, you do see curving streets,” Boeing says.
But because his algorithm measures the angle between the two closest intersections—without regard to the twists and turns between—these set-ups tend to register as more orthogonal than they look on a map. Histograms of true suburbs, like Moraga, California, in the hills of the East Bay, show a more expected “eyeball” pattern.
While grids alone do not tell the stories of cities, they can be useful in comparing, contrasting, and helping establish patterns across continents and countries. Visualizations of these phenomena can help urbanists share findings with the public, too.
Read more about Boeing's compass-like maps here.