Measuring sprawl in large Chinese cities along the Yangtze River via combined single and multidimensional metrics

Large cities in developing countries such as China are increasingly experiencing urban sprawl. Urban sprawl in Chinese cities has resulted in overwhelming problems, such as inefficient use of urban land, loss of farmland, and environmental degradation, all of which pose challenges to urban sustainability. To investigate urban sprawl in the Chinese context, seven large cities in the Yangtze River Economic Belt were compared. An integrated framework combining single-indicator and multidimensional-indicator measurements was employed to quantify the magnitude of sprawl. Urban spatial expansion was determined by spatially simulating the built-up area for each city based on DMSP/OLS nighttime light data, population census, and statistical data in 1992, 2000, and 2010. The single-indicator measurement employed a comprehensive metric of growth ratio to represent the mismatch of land expansion and population growth. Multidimensional measurement was composed of three key dimensions of sprawl, namely, low density, discontinuity of land use, and poor accessibility. In most cases, results of the single-indicator measurement were generally consistent with the results of the multidimensional measurement. The case study demonstrated the applicability of the new measurement framework in quantifying sprawl. The major features of sprawl, policy implications, and usage of methods were discussed.