Integrating GIS and urban spatial system dynamic model for urban expansion analysis

Urban evolution model is an assistant analysis method for urban planning which can effectively trace the urban development process of the past and predict the possible evolution scenarios in the future. This paper proposed urban spatial system dynamic model (USSD model) by coupling strategy between Geographic Information System (GIS) and urban System Dynamic (SD). GIS can deal with the static spatial relationships while SD can deal with the dynamic relationships of complex spatial system. This new urban expansion model can predict the expansion scenarios in the future according to tracing the urban development of the past. It considered the spatial relationships among urban system elements as well as the dynamic links and interactions among the spatial elements over time. It is achieved through a dynamic data exchange between GIS and SD. Firstly we analyzed urban system by using five subsystems: population, resources, transportation, land usage and soil erosion. Secondly, we have developed USSD model based on dynamic links among the subsystems. Thirdly, we have created five layers in GIS and operated them in the USSD model. Finally, a case study illustrated the USSD model in Wuhan city. It is concluded that the USSD model is an efficient tool for forecasting the urban expansion with its advantages on dealing with the spatio-temporal problem.