Spatial Patterns of Distinct Urban Growth Forms in Relation to Roads and Pregrowth Urban Areas: Case of the Nanjing Metropolitan Region in China

Abstract

Urban growth can present distinct geometric forms, the patterns and determinants of which remain little understood. The aim of this study is to explore the spatial patterns of different urban growth forms (UGFs) in relation to roads and pregrowth urban areas (PUAs) in the Nanjing metropolitan region of China. Three basic UGFs—infilling, edge-expansion, and spontaneous growth—were distinguished using a topological quantitativecriterion. Results from the UGF composition showed the growth of Nanjing City, China, tended to be less compact during the accelerated urbanization. The three UGFs generally showed exponential attenuation with increasing distance to roads and PUAs, while spontaneous form showed a lognormal relationship with PUAs. Results from the logistic regression suggested that PUAs had a stronger tendency to attract infilling and edge-expansion growth than roads, whereas roads were a stronger attractor of spontaneous growth. Overall, this study can provide better understandings on the evolution of urban morphology at the landscape scale as well as useful implications for urban planning.An alert of exacerbated urban sprawl in Nanjing, China, was raised and the importance of road planning in the effort to control sprawl was highlighted.