1. a Institute of Geodesy and Geophysics , Chinese Academy of Science , Wuhan, 430077, China
2. b Advanced Research Centre for Spatial Information Technology , Department of Land Surveying and Geo‐Informatics , The Hong Kong Polytechnic University , Hong Kong
3. c Zhengzhou Institute of Surveying and Mapping , Zhengzhou, 450052, China
4. d Inform S.r.l. , Environmental Technology Department , Digital Mapping Sector , I–35129 Padova, Italy
5. e State Key Laboratory of Information Engineering in Surveying , Mapping and Remote Sensing , Wuhan University , Wuhan, 430079, China