国家自然科学基金41171305,41171354,40701157;信息工程大学地理空间信息学院硕士学位论文创新与创优基金S201403Foundation support:The National Natural Science Foundation of China.41171305,41171354,40701157;Master’s Degree Dissertation Innovation Fundation of Geospatial Information Institute,Information Engineering UniversityS201403