Urban sprawl is the unplanned spreading of urban development out towards fringes of the city. Our visualization helps users understand the factors that influence urban sprawl, and what factors are common amongst cities with similar sprawl statistics. It consists of two linked parts: a scatterplot and a star plot.
sprawl_1976_92: Sprawl index for 1976-92 development. Percentage of land not developed by 1992 in the square kilometre around an average 1976-92 residential development in each metropolitan area.
sprawl_1992: Sprawl index for 1992 development. Percentage of land not developed in the square kilometre around an average residential development in each metropolitan area in 1992.
sprawl_1976: Sprawl index for 1976 development.
central_empl_1977: Centralized-sector employment 1977. Related to the mean percentage of metropolitan area employment for each SIC sector that is found within three miles of the central business district.
avg_dec_popgr1920_70: Mean decennial percentage population growth 1920-70. Taken from data from the census conducted every ten years.
pc_aquifer_fringe: Percentage of urban fringe overlaying fresh-water aquifers.
elevat_range_msa: Elevation range in the MSA (in metres). The difference between the maximum and the minimum elevation in the metropolitan area.
ruggedness_msa: Terrain ruggedness index in the MSA (in metres). This is an index of the average terrain ruggedness that determines elevation of points 90 metres apart.
cooling_dd: Mean cooling degree-days. Cooling degrees on a given day are zero if the average temperature is below 65 °F (about 18 °C) and the degrees by which the average temperature exceeds 65 °F otherwise.
heating_dd: Mean heating degree-days. Mean annual heating degree days are similarly calculated by summing degrees below 65 °F over all days in a year.
rest_bars: Bars and restaurants per thousand people.
road_density: Road density in metres per hectare. Metres of major road (interstate, other limited access, divided highway, other U.S. highway, other state primary highway, state secondary highway, improved road, parallel highway, toll road) per hectare.
popgr_1970_90: Percentage of population growth between 1970-90.
We use the dataset originally created for the article "Causes of Sprawl: A Portrait from Space", published in the Quarterly Journal of Economics in May 2006. In particular, we make use of the companion website created by one of the article's authors, Diego Puga. His site contains a summary of the article, the CSV file we use that contains the raw data, and detailed descriptions of the data variables.