Airborne LiDAR Bathymetry in Close Up

RIEGL tested the performance of its topo-bathymetric airborne laser scanning system, the VQ-840-G, in a transition zone context along the French Mediterranean coast.

Initially planned as a UAV survey, tests were conducted using a fixed-wing aircraft due to the restrictions placed on operations by the ongoing coronavirus pandemic. The results are encouraging, and the next step will be drone operations in more challenging sea conditions.

The test was performed on March 2, 2021 at Cap Sicié, a cliff off the bay of Toulon and La Seyne sur Mer in the French Provence area of Var. To the east, an eye-catching twin rock formation, ‘Les Deux Frères’, served as a focus for data acquisition.

First analysis of the LiDAR data showed that the topographic parts provided reliable multi-echo coverage, thus well capturing terrain beneath vegetation. The seafloor in the measurement area is composed of sand, which provides good reflectance due to its color, yet causes water turbidity when disturbed.

In order to reference and validate the results, the data was compared with existing, publicly available ALB LiDAR data obtained by SHOM (the French Naval Hydrographic and Oceanographic Service).