The Many Layers of a City

"Centers all the way down: a study of centrality in the modern city"

Moving through the city, one interacts with the city on varying scales and activity levels. While one may work in the center of a dense business district, she or he enters new, smaller city centers when they stop for groceries or a pint of beer on the way home. In a 2011 thesis out of Georgia Tech titled “Centers all the way down: a study of centrality in the modern city,” Patrick Sewell (MCRP '11) argues that by exploring the concept of a city center more comprehensively, planners are better able to understand all the forces that shape a city.

To examine the hierarchy of city centers distributed throughout Atlanta, Sewell utilized Georgia Tech’s SMARTRAQ dataset to map the distribution of commercial activity. He then used kernel density estimation and several other quantitative and qualitative analyses to objectively compare Atlanta’s hierarchy of centers with commonly held notions of centrality throughout time.

Sewell’s research shows “that beneath Atlanta’s urban fabric, there exists complex logic generating a hierarchial structure of centers at multiple scales.” This supports the theory that centrality develops by a dual process: through the minimization of distance in the global network and the through the intensification of street patterns in the local road network. Like all urban places, Atlanta’s hierarchy of city centers forms complex layers of meaning, the very complexity necessary for good, urban life.

Patrick Sewell is a 2011 graduate of Georgia Tech’s School of City and Regional Planning and currently works as a Credit Risk Analyst at Regions Financial Corporation. Professors John Peponis, Michael Dobbins, and Perry Yang served on Sewell’s thesis advisory committee.

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