A Multi-Level and Multi-Dimensional Measuring on Urban Sprawl: A Case Study in Wuhan Metropolitan Area, Central China

Chinese cities are experiencing rapid urban expansion and being transformed into more dispersed urban form which necessitate the quantification of fine-scale intra-urban characteristics for sustainable urban development. We propose an integrated multi-level and multi-dimensional method to characterize urban sprawl and apply it to Wuhan, a typical metropolitan area in central China from 1996 to 2006. The specifications of levels are parcel at micro-level, district at meso-level and metropolitan area at macro-level. The measurements are implemented in seven dimensions: composition, configuration, gradient, density, proximity, accessibility and dynamics. Metrics are assigned to each dimension and innovative metrics such as derived contagion index, distance-based correlation coefficient and weighted centroid migration are defined to quantify the sprawling process. This bottom-up approach is capable of exploring spatio-temporal variation of urban growth at finer scales, capturing the multi-dimensional features of urban sprawl and providing policy implications for authorities at different levels. The results reveal that industrial sites and built-up land for special use are the most scattered and randomly distributed land use types, parcels and districts at the urban fringe present higher fragmentation than those in the urban core areas and urban expansion is largely enforced by assigning development zones.