Fig. 1. The location of Longyang Gorge and its three interested slopes near the dam bank

Fig. 2. Overall technical route

Fig. 3. UAV LiDAR data acquisition flight route planning

Fig. 4. UAV oblique images flight route planning

Fig. 5. Schematic diagram of radius filtering denoising algorithm

Fig. 6. Missing compensation by fusing LiDAR point cloud and point cloud from oblique images

Fig. 7. Complete DEM with 1 m resolution of high steep slope

Fig. 8. Deformation results of three steep slope

Fig. 9. Steep slope direction map of Nongchang

Fig. 10. Slope map near water region of Nongchang steep

Fig. 11. Schematic diagram of collapse and stacking

Fig. 12. Main sliding direction profile