作者单位:Ying Li,Qiming Zeng(Institute of Remote Sensing and GIS,Peking University,Beijing,P.R.China,100871;Key Lab of Spatial Information Integration and Engineering Application of Beijing)李颖,曾琪明(北京大学遥感与GIS研究所,北京100871;北京大学北京市空间信息集成与3S工程应用重点实验室,北京100871)Wanqing Zheng,Shuyi Zhang(School of mathematical science,Peking University,Beijing,P.R.China,100871)郑婉勤,张树义(北京大学数学科学学院,北京100871)