Lidar Bathymetry

Lidar bathymetry is airborne or vessel-based laser scanning of the shallow seabed, using a green laser near 532 nm that penetrates clear water while an infrared pulse marks the surface; the time difference between surface and bottom returns gives depth. Airborne lidar bathymetry maps coastal zones at high point density to depths near 50 m in very clear water, more typically 1.5 to 3 times the Secchi depth. It bridges the land-sea zone where vessels cannot run safely and acoustic systems lose shallow coverage. Water clarity is the binding constraint; turbid or tannic water sharply limits penetration. Survey accuracy is graded against IHO S-44.