Quantifying the sustainability of urban growth and form through time: An algorithmic analysis of a city's development

- Geographic data was used to reconstruct a 75-year history of a mid-sized city.
- Sustainability of urban form through time can be determined using planning metrics.
- Algorithmic analysis of a city's characteristics yields sustainability of urban form.
- Changes in urban form and population density reflect suburbanization of the city.
- The change from a gridded city to a suburban form led to less sustainable metrics.

Throughout the latter half of the 20th century, households and cities have changed dramatically. Dense urban developments have given way to lower density suburbanization, while the changing face of the typical family has led to different household makeups. Analyzing how changing urban form influences the sustainability of cities is important for planning future ways in which society aggregates itself. Using current data layers, such as urban boundaries and building footprints, along with past aerial photographs of the city and census data, a detailed reconstruction of the city of Pocatello, Idaho was possible for 1941 for both urban form and population. Using these data sources an algorithmic analysis of various aspects of the city, clustering, compactness, connectivity, and density, was performed on a decadal basis. Results showed an overwhelming trend toward less sustainable development for the city, larger blocks, measured by intersection density, larger distances between houses, fewer people utilizing more space, a more irregularly shaped urban form, an average greater distance from the city center for development, and decreased connectivity, as measured by intersection density. Because the data sources used for this study are readily available to most planning municipalities, the same analysis could be performed on various cities and metros across the United States.