Thursday, June 26, 2014

Visualizing Sprawl

Some big US cities are dense, while others are spread out. This affects the economy, quality of life, and the environment. Here's a way to visualize the residential density of the country's 12 largest regions and their varying levels of sprawl.

Residential density of census tracts in and around the District of Columbia and Baltimore
(magnified 200% in each direction, relative to visualizations below)

Earlier this year, Smart Growth America released a report titled Measuring Sprawl 2014, finding that New York is the country's "most compact, connected large metro area," with an index score of 203.4, while Atlanta is the "most sprawling," with a score of 41.0.

But what does that gap really look like? The world's most iconic skyline on one extreme, contrasted with a highway full of motorists stranded overnight due to a snowstorm on the other? What about viewed through a wider angle lens, at a regional level? Next City recently published a series of GIFs illustrating regional sprawl over time, and this post tells a similar story from a different perspective.

The visualizations below show residential density (as one unit of height for every person per square mile), by census tract, for the nation's 12 statistical areas of at least 5 million inhabitants. The images show Combined Statistical Areas (CSAs) with the exception of Miami, which until recently was not part of a CSA. The regions are viewed from the same height and distance, but from different directions, most often from the south.



Note: One census tract, 307.2 in Chicago, was omitted from this visualization as its population density is off the charts. The tract essentially encompasses only the land on which these three high rises are located.

Cross-posted on Greater Greater Washington

1 comment:

  1. It's tough to ensure that you're using consistent scales in these maps. You need consistent x, y, and z coordinates, and then you're asking viewers to compare "peakiness" of the data. Not an easy task!

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