ROV-mounted high-resolution bathymetry data (ASCII CSV format) acquired at vertical deep-sea habitats, Galápagos Islands, 2023 (FKt230918)

ROV SuBastian-mounted multibeam echosounder data for high-resolution mapping of steep, vertical and overhanging cold water coral reefs of the Galápagos, Ecuador, was collected during Falkor (too) cruise FKt230918 in 2023. The Norbit Wideband Multibeam Sonar Basic system was mounted on the light bar on the front of the ROV vehicle, in a fully forward orientation, rotated 90 degrees to port. Mapping was done in parallel, lateral passes at a constant distance from a vertical cliff, keeping the heading as constant as possible. A constant sound velocity was used, as measured by the integrated sound velocity probe on the Norbit system at the transducer. Navigation and attitude data from the SprintNav system underwent a double coordinate transformation and double rotation using a bespoke routine in R, after which the new navigation and attitude data were imported with the bathymetry and ROV depth data in Qimera v2.4.9. The MBES data were processed in a user-based coordinate system, as if it was recorded in a conventional downward facing set-up. Once processed, the final point clouds and grids were exported at 15cm or 25cm resolution and back-rotated/transformed to their correct geographical location. The data files are in ASCII XYZ comma-separated format and are either in geographical WGS84 coordinates or in UTM meters as indicated in the file name. The UTM zone is 15S except for the data from dive SO587 which is UTM zone 15N. The grid resolution is 15cm or 25cm and is given in the file name. Funding for the project was provided through CLASS Grant No: NE/R015953/1, SOI FKt230918.