Analysis of the green light penetration from Airborne LiDAR Bathymetry in Shallow Water Area

Abstract An Airborne LiDAR can be used to map the depth of the water. This system is called an Airborne LiDAR Bathymetry. In order to measure the water depth, an Airborne LiDAR is utilized with the green light sensor beside the near-infrared light sensor. However, water condition affects the capability of the green light penetration. The clarity of the water and the vegetation are some of the restriction for green light to penetrate the water especially in inland water areas. The research examined the penetration capability of the green light of the Airborne LiDAR Bathymetry in shallow water areas. A comparison of depth values derived from the LiDAR system and the direct measurements was performed to asses the penetration accuracy of the green light. The depth comparison is derived from eleven channels in the research area. The direct measurement was conducted by using a tape to measure the depth, and the RTK GNSS to measure channel’s dimension. A Secchi Disk also used to measure the turbidity of the water. The vertical reference for the depth is Earth Gravitational Model 2008 (EGM 2008). Based on the research, the depth difference between LiDAR Bathymetry and the direct measurement ranges from 0.02 m to 0.22 m. The vertical accuracy of the LiDAR Bathymetry is 0.239 m within 95% of confidence level.