On the application of a concentric zone model (CZM) for classifying and extracting urban boundaries using night-time stable light data in Urumqi of Xinjiang, China

Abstract

ABSTRACTNight-time satellite imagery provided by the Defense Meteorological Satellite Program’s Operational Linescan System (DMSP−OLS) is widely used in monitoring urban construction area. However, there are still large uncertainties in validating such applications across different regions. In this study, we use the concentric zone model (CZM) to classify the night-time light emission data to define the urban area. Using this new classification method, we have revealed the urban development in Urumqi, a large city in the newly proposed Silk Road Economic Development Belt. Our results show a range of thresholds for defining Urumqi boundary. Comparing the city boundaries from 2002 to 2012, the city did not show significant expansion during the period of 2002–2007 except for a northward expansion. From 2007 to 2012, the city has expanded outward by about 6 km and the surrounding terrain appears not to be a major obstacle to its development. In this study, we have demonstrated that through the analysis of the layer structure of the night-time light emission data, the evolution of the Urumqi city has been clearly demonstrated. Therefore, using CZM to classify night-time stable light data is a practical method for studying urbanization.