bathymetricLiDARjärjestelmät

Bathymetric LiDAR is an airborne remote sensing technique that uses green laser light to map submerged surfaces, including coastlines, shallow seas, rivers, and lakes. It records returns from the water surface and the seabed, enabling depth measurements and the production of bathymetric digital elevation models for shallow coastal zones.

The system emits short laser pulses toward the water and records the time of flight for surface and bottom returns. The green wavelength, typically around 532 nanometers, can penetrate clear water, and depth is estimated from the time difference, with corrections for water refraction and air–water geometry. Georeferencing is achieved with onboard GNSS and inertial navigation systems.

Outputs include 3D point clouds, bathymetric DEMs, and orthophotos. Processing may involve water-column correction, bottom detection, alignment with above-water lidar, and tidal adjustments.

Applications include coastal mapping, harbor surveys, flood risk assessment, habitat mapping, and infrastructure planning. Bathymetric LiDAR is fast and covers large areas but is limited to shallow, clear water and can be impaired by turbidity, bottom type, glare, or rough sea state.

Compared with active sonar, bathymetric LiDAR provides high-resolution surface data over wide areas but typically yields shallower penetration and depends on surface conditions and water clarity.