1.Geographic Information Center, Surveying and Mapping Institute of Beijing, Beijing 100038, China; 2.School of the
Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China; 3.China Aero Geophysical
Survey & Remote Sensing Center for Land & Resource, Beijing 100083, China; 4.Land Investigate Department , China
Land Surveying and Planning Institute, Beijing 100029, China