利用DM SP/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

Research on the layered threshold method for extracting urban land using the DM SP/OLS stable nighttime light data

DMSP/OLS夜间灯光数据是提取大尺度城镇用地信息的有效数据手段。利用DMSP/OLS稳定夜间灯光数据,在传统二分比较法的基础上,发展一种提取城镇用地信息的新方法——分层阈值法。该方法采用分层分类的思想,不断地将灯光阈值相近的行政单元划分到相同的集合,直至集合内各行政单元的灯光阈值完全相同为止。基于分层阈值法,从2002年DMSP/OLS稳定夜间灯光数据中提取中国内地的城镇用地信息,并利用统计数据和Landsat ETM+数据分别从数量特征和空间格局上对提取结果进行精度评价。研究结果表明,分层阈值法不仅克服了传统二分比较法需要逐个行政单元求取阈值导致计算效率较低的缺陷,优化了阈值求解过程,提高了城镇用地信息提取效率,而且具有较高的可靠性和推广应用价值。

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.