Research on the layered threshold method for extracting urban land using the DMSP/OLS stable nighttime light data
利用DMSP/OLS稳定夜间灯光数据提取城镇用地信息的分层阈值法研究

DMSP/OLS nighttime light data is effective and economical for mapping urban land on a large scale. Based on conventional dichotomy method, Layered Threshold Method (LTM) was developed to extract the urban land using the DMSP/OLS stable nighttime light data. The administrative regions with close thresholds were divided into the same set by LTM continually. The process was ended until the thresholds in one set were selfsame. The urban land of Chinese mainland in 2002 was extracted based on LTM using the DMSP/OLS stable nighttime light data. Compared to the traditional inefficient dichotomy method, whose efficiency depended on the amount of administrative regions, LTM searched the thresholds of the sets instead of each administrative region, optimizing the previous method. The performance of the LTM was evaluated to be credible and valuable according to statistical data and Landsat ETM+ data.