1. School of Geomatics and Urban Spatial Informatics, Beijing University of Civil Engineering and Architecture, 1 Zhanlanguan Road, Beijing 102616, China
2. Key Laboratory of Urban Spatial Informatics, Ministry of Natural Resources of the People’s Republic of China, 15 Yongyuan Road, Beijing 102616, China
3. Department of Civil Engineering, Toronto Metropolitan University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
4. College of Geosciences and Surveying Engineering, China University of Mining and Technology, Beijing 100083, China