Measuring Urban Sprawl

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Measuring Urban Sprawl

Published Wednesday, April 26, 2006 by CCAer | E-mail this post

The Neptis Foundation, a Toronto-based organization that focuses on urban development, has utilized satellite and air photo data to create a 8.7 billion data cell image depciting land development in the United States. According to a paper entitled “Causes of Sprawl: A Portrait form Space” that will be appearing the Quarterly Journal of Economics, Pittsburgh is more sprawling than Miami and recent development in Boston is more scattered than in Los Angeles.

“The authors merged high-altitude photos from 1976 with satellite images from 1992 (the most recent available) to create a grid of 8.7 billion 30-metre by 30-metre cells that tracks land use changes nationwide,” says a University of Toronto press release. “The authors also investigated why some cities are more sprawling than others. They found that a city's climate, topography and access to groundwater account for 25 per cent of the nationwide variation. When the climate is temperate, people spread out to have more space to enjoy the weather. Hilly places see more scattered development as people avoid the costs of building on hillsides -- but mountains act as a barrier and lead to more compact development. Places with easy access to groundwater see more scattered development, since people can supply remote houses with water by drilling inexpensive wells rather than paying for water lines.”

Read a version of the paper in pdf format. An 11 x 17 version of the land development image of the United States is also available as are other, more detailed images of various American cities.

3 Responses to “Measuring Urban Sprawl”

Anonymous on 11:12 PM

Old Data; Older Ideas

A 'sprawl' study published in 2006 based on 1992 remote sensing data? At the very least, the authors could have bothered to analyze the Landsat 7 data available free, online, collected in 1999/2000. And they still would've had those 8.7 billion cells of which they seem very proud.

But that's small beer when the authors tip their hand in the first paragraph by referencing that great touchstone of academic relevance--a public opinion study! Which notes, apparently, that 82% of the public isn't exceedingly troubled by what's implied by the pejorative term "sprawl". But pressing on, we're treated to tables of important data that indicate...people prefer more space to less?

And we're still referencing, early and often, the monocentric city model! Well, in case you didn't catch Peirce Lewis' work in the late 80s/early 90s, which was popularized by Joel Garreau in 'Edge City', who was in turn even more popularized by Tom Wolfe in 'A Man In Full', terms like "monocentric" and "CBD" aren't quite as useful as they used to be. OK, so the authors mentioned above are a little too readable for academic tastes, but hey, occasional slumming has its rewards.

And don't exert yourself researching the relationship of 'sprawl' to phenomena such as the rise of the service sector, the decline of manufacturing, the economics of agriculture, plunging transportation costs for goods, and female participation in the workforce: those data probably aren't available in a pre-packaged remote sensing data set.

Finally, thanking Ed Glaeser is a nice touch--I imagine he was reassured that he won't be outshined by this crew on an academic panel anytime soon.

I hope for their own sakes the authors already have tenure.

BT
Anonymous on 11:32 PM

Old Data; Older Ideas

A 'sprawl' study published in 2006 based on 1992 remote sensing data? At the very least, the authors could have bothered to analyze the Landsat 7 data available free, online, collected in 1999/2000. And they still would've had those 8.7 billion cells of which they seem very proud.

But that's small beer when the authors tip their hand in the first paragraph by referencing that great touchstone of academic relevance--a public opinion study! Which notes, apparently, that 82% of the public isn't exceedingly troubled by what's implied by the pejorative term "sprawl". But pressing on, we're treated to tables of important data that indicate...people prefer more space to less?

And we're still referencing, early and often, the monocentric city model! Well, in case you didn't catch Peirce Lewis' work in the late 80s/early 90s, which was popularized by Joel Garreau in 'Edge City', who was in turn even more popularized by Tom Wolfe in 'A Man In Full', terms like "monocentric" and "CBD" aren't quite as useful as they used to be. OK, so the authors mentioned above are a little too readable for academic tastes, but hey, occasional slumming has its rewards.

And don't exert yourself researching the relationship of 'sprawl' to phenomena such as the rise of the service sector, the decline of manufacturing, the economics of agriculture, plunging transportation costs for goods, and female participation in the workforce: those data probably aren't available in a pre-packaged remote sensing data set.

Finally, thanking Ed Glaeser is a nice touch--I imagine he was reassured that he won't be outshined by this crew on an academic panel anytime soon.

I hope for their own sakes the authors already have tenure.

BT
Anonymous on 2:57 PM

I agree with BT, plus the yellow on gray makes it challenging to gauge non-sprawling places.

Ongoing question - what drives spawl. Maybe median home prices, % unemployement, and pro-sprawl General Plans weigh heavily. I know from living in Northern Cal., anti-sprawl initiatives, open space, and public lands hamper spawl here and there.

I don't think people move to cities for home or work due to its climate, topography, and groundwater levels, maybe we'll be thinking that way when things heat up in a few hundred years.