Fig. 1. Schematic diagram of DBSCAN

Fig. 2. Flow chart of point cloud filtering algorithm based on density clustering

Fig. 3. Simulation map of laser point cloud position in large survey area

Fig. 4. 3D view of S53

Fig. 5. Elevation map of S53

Fig. 6. Filtering result map of S53

Fig. 7. Error point location map of S53

Fig. 8. Relief image after filtering of S53

Fig. 9. Section plane comparison diagram of S53

Fig. 10. Schematic diagram of classification error

Fig. 11. 3D view of S61

Fig. 12. Elevation map of S61

Fig. 13. Filtering result map of S61

Fig. 14. Error point location map of S61

Fig. 15. Relief image after filtering of S61

Fig. 16. Section plane comparison diagram of S61

Fig. 17. 3D view of S21

Fig. 18. Filtering result map of S21

Fig. 19. Relief image after filtering of S21

Fig. 20. Error point location map of S21

Fig. 21. Mutation point location map of S21

Fig. 22. Re-division result map of S21

Fig. 23. Relief image before filtering of S24

Fig. 24. Elevation map of S24

Fig. 25. Filtering result map of S24

Fig. 26. Error point location map of S24

Fig. 27. Relief image after filtering of S24

Fig. 28. Section plane comparison diagram of S24

Fig. 29. 3D view of S71

Fig. 30. Filtering result map of S71

Fig. 31. Relief image after filtering of S71

Fig. 32. Error point location map of S71

Fig. 33. Mutation point location map of S71

Fig. 34. Re-division result map of S71