The National Natural Science Foundation of China.41471387,41201477,41301526,41501506;The Open Research Foundation of State Key Laboratory of Geo-information Engineering Nos.SKLGIE2015-M-3-1,SKLGIE2015-M-3-2国家自然科学基金41471387,41201477,41301526,41501506;地理信息工程国家重点实验室开放研究基金SKLGIE2015-M-3-1,SKLGIE2015-M-3-2