Near-bottom ROV LiDAR bathymetry grid (ESRI ASCII format) from the Octopus Garden hydrothermal spring site

Near-bottom high-resolution bathymetry data were collected with a 3D at Depth Wide Swath Subsea Lidar (WiSSL) laser scanner that is part of the MBARI Low Altitude Survey System (LASS) mounted for two dives in 2021 to the ROV Doc Ricketts, which was flown at 3 m altitude at speeds <= 1.0 m/s to produce bathymetry from the lidar, presented here at 2 cm resolution. Each sounding has a 532 nm laser footprint of 0.8 cm. The grid file presented here is in ESRI ASCII format and the projection is UTM zone 10N. Position and attitude data were provided by a Kearfott SeaDevil Inertial Navigation System (INS) integrated with a 1200 kHz Teledyne RD Instruments Doppler velocity log (DVL) and a Paroscientific pressure sensor. The LASS sensor package was mounted in an articulating frame within an ROV tool sled that rotates from pointing the sensors vertically down to horizontally forward, allowing surveys of flat to vertical seafloor. The articulation is automated by closing a control loop around the difference between the forward and backward beams of the DVL. Funding was provided by a grant from the David and Lucile Packard Foundation to MBARI.