The spatiotemporal change of urban form in Nanjing, China: Based on SLEUTH and spatial metrics analysis

This study explores the combined application of remote sensing, spatial metrics and urban model to analyze the urban form change of Nanjing city, China since 1979. The investigation is based on a nearly 30-year time series data set compiled from interpreted satellite imagery. The SLEUTH urban growth model which based CA was calibrated using the multitemporal data sets for the entire study region and predicted the urban growth to the year 2020. Spatial metrics coming from landscape metrics were used both specifically to assess the impact of urban development in four periods, and generally to analyze the spatial and temporal dynamics of urban form. The results illustrate the utility of modeling in explaining the amount and spatial change of urban form. The result suggested that the change of urban form show a period of urban sprawl and diffuse growth in the time of 1979 and 2000. After the year of 2008, spatial complexity declined as most of the urban areas grew more compact through infilling, developing the vacant land between the sprawling urban patches. The combined approach using remote sensing, spatial metrics and urban modeling may prove a productive new direction for the improved understanding, representation and modeling of the urban spatiotemporal patterns. Although the integrated approach is powerful, the forecasting of urban form remains problematic and could benefit from further research on spatial metrics and urban model.