1. Faculty of Geosciences and Engineering, Southwest Jiaotong University, Chengdu, People's Republic of China
2. Faculty of Geomatics, Lanzhou Jiaotong University, Lanzhou, People's Republic of China
3. Department of 3D Spatial Information, Sichuan Smart Map Spatial Information Technology Co., Ltd., Chengdu, People's Republic of China
4. Department of 3D Spatial Information, Zhejiang Hi-Target Navigation Tech Co., Ltd., HuZhou, People's Republic of China
5. Department of Surveying and Geographic Information, Chengdu Institute of Survey & Investigation, Chengdu, People's Republic of China