Zhiguo Zhou, Lingli Zhao, School of Remote Sensing and Information Engineering, Wuhan University, Wuhan, China, China; Hongtao Shi, School of Environment and Spatial Informatics, China University of Mining and Technology, Xuzhou, China, China; Weidong Sun, Lei Shi, Jie Yang, The State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, China, China