Fractal Dimensions of Spatial Structure of Urban Agglomeration in the Yangtze Delta

Urban agglomeration provides the framework for the evolution of spatial structure of urban sprawl.The spatial distribution of urban agglomeration is non-scaling due to the self-similarity of urban system,which could be illucidated by fractal dimensions.In this paper the urban agglomerations in the Yangtze Delta consisting of 16 prefecture-level cities,or 74 municipal districts and counties were chosen as the studying area.The software ArcGIS was employed to calculate 3 kinds of fractal dimensions,namely,aggregation dimension,grid dimension and spatial correlation dimension,with basic data downloaded from National Fundamental Geographic Information System(NFGIS).The aggregation dimension could be used to describe the spatial aggregan of urban agglomeration,the grid dimension to describe spatial equlibrium and the spatial correlation dimension to describe the spatial interaction between urban agglomerations.The results indicate that the urban agglomerations in the Yangtze Delta are of multi-centers with the regional central cities of Shanghai,Nanjing and Hangzhou.The distribution density of municipal districts and counties gradually decreases from the central cities to the periphery.The urban agglomerations in the Yangtze Delta are relatively evenly distributed and their fractal characteristics are complicated.The convenient transportation infrastructure in the Yangtze Delta promotes spatial interaction between urban agglomerations,which is beneficial for regional integrated development.