Urban spatial growth analysis from satellite-derived imperviousness in an oasis city

Oasis cities are the special regions in arid zones, which have the densest human activities and the most sensitive relationship between human and natural environment. Rapid urbanization of oasis cities of Xinjiang, China has impacted on the stability and economic sustainable development of the region during the past decade. Therefore, monitoring urban spatial growth and land cover change brought on by urbanization has been a critical concern to urban land management decision-making, ecosystem monitoring, and urban planning. In this research, we investigate the usefulness of satellite-derived imperviousness as an alternative for urban spatial growth characterization. The research consists of two procedures. Firstly, this study explored extraction of impervious surface information from Landsat TM data in 1987 and 2007 acquired over Urumqi, Xinjiang with the integration of fraction images from linear spectral mixture analysis based upon Ridd's vegetation-impervious surface-soil (V-I-S) model. Accuracy assessment indicated that the mean RMS errors are less than 0.02. Secondly, we analyzed the spatio-temporal changing trend of imperviousness with the visual inspection and emphasis upon some “hot” spots of development areas. We conclude that satellite-derived imperviousness is able to serve as a timely and cost-effective manner for objective assessment of the oasis urban spatial growth in arid region.