A GIS-based buffer gradient analysis on spatiotemporal dynamics of urban expansion in Shanghai and its major satellite cities

摘要

A GIS-based gradient analysis is a useful tool for exploring spatiotemporal dynamics of urban land-use. Although some case studies have been conducted confirming the efficacy of this approach, the gradient analysis of large-scale regional urbanization has still been seldom documented, and the urbanization of satellite cities and their interactions with a central city in regional urbanization have also been poorly explored. In this study, a combination of remotely sensed data, urbanization metrics and GISbased buffer gradient analysis is employed to analyze the overall spatiotemporal characteristics of urban expansion in the Shanghai region, China, and to explore the urbanization of its major satellite cities and their interactions. The results show the overall spatiotemporal changes in the urbanization gradient are largely influenced by the distance from the urban center, yet there are distinct spatial variations mainly resulting from the interactions of the urbanization of the central city with that of satellite cities. The urbanization within the urban-suburb transitional zones generally had a specific rhythm of intensity and weakness, which can function as the spatial signatures to analyze and demonstrate similar or other types of urbanization processes. The major satellite cities of the Shanghai region showed their distinct temporal-spatial characteristics in their urban expansion behaviors, and thus can be categorized as autonomous, passive, steady and irregular modes of urbanization. Key words: Urban expansion;; Spatiotemporal;; Buffer analysis;; Satellite city;; Shanghai;; China