Can a simple graph communicate the complexity of a city plan? That was the question developed by University of California Berkeley professor Geoff Boeing during his urban planning dissertation. The result is an elegant visualization method that shows how simple–or crazily complicated–a city’s grid is, using just a single image.
To create the viz, Boeing developed a Python software application that analyzes the orientation–for instance, north/south, east/west, or more complex variations in between–of every street in a given city (in this case, he analyzed 25 cities). The software, which you can download from his page, records the orientation of every street it finds, obtaining a frequency for each orientation. It places the frequency of each orientation on a polar histogram.
“Each bar’s direction represents the compass bearings of the streets and its length represents the relative frequency of streets with those bearings,” Boeing explains on his research page. If you look at the Manhattan diagram below, you’ll see that almost half of its streets are oriented north to south and almost the other half are oriented east to west, with the rest of them–mostly the old streets in the southern tip of the island–are distributed in various compass orientations. Those are represented by the small bars at the center of the diagram, which clearly conveys the idea that Manhattan is a relatively orderly city.
Boston, by comparison, has a wildly disorganized street grid, with a hugely varied distribution of orientations. “We can learn something about the spatial ‘logic’ of the city,” Boeing said via email. “While these visualizations don’t tell us about the scale or grain of the urban fabric, they do tell us about how the circulation network is oriented. These street networks organize all the human activity and circulation in the city . . . Some are very carefully and deliberately planned with certain design paradigms, development goals, transportation technologies in mind,” he continues, while “others are very organic.”
In the end, Boeing analyzed 25 cities in total, creating a comprehensive visualization of American city planning paradigms. While understand the complexities of the urban fabric in total can be nearly impossible, his images synthesize thousands of datapoints into a single easily-digestible graphic. For him, “these visuals can help make otherwise dry or technical city planning concepts more salient and approachable for laypersons. You can easily see and comprehend your own city and how it relates to others’ patterns.”