NOAA's NOS/NCCOS/CCMA Biogeography Team, in collaboration with NOAA vessel Nancy Foster and territory, federal, and private sector partners, acquired multibeam bathymetry data in the US Virgin Islands from 2/18/04 to 3/5/04 and 2/1/05 to 2/12/05. Data was acquired with a pole-mounted Reson 8101 ER multibeam echosounder (240 kHz) and processed by a NOAA contractor using CARIS HIPS v5.4 software. Data has all correctors applied (attitude, sound velocity) and has been reduced to mean lower low water (MLLW) using final approved tides from NOAA COOPS. Data is in UTM zone 20 north, datum NAD83. The processed CARIS data was used to generate a CARIS BASE surface based on swath angle. A comma delimited ASCII XYZ file was then exported from the BASE surface.
While these projects were conducted to meet IHO Order 1 and 2 accuracy standards, dependant on the project area and depth. All users should individually evaluate the suitability of this data according to their own needs and standards.
For the 2005 project, the Chief Scientist was NOAA/NOS/NCCOS/CCMA's Tim Battista and the Lead Hydrographer was independent contractor Jay Lazar. Data was collected aboard the NOAA ship Nancy Foster from 2/1/05 to 2/12/05, as project number NF-05-05-VI. Multibeam data was acquired in GSF format with a pole-mounted Reson 8101 ER multibeam echosounder (240 kHz), with options 033, 037, and 040. Reson backscatter snippet collection was enabled. SAIC ISS 2000 software was used to interface with the Reson system. Line spacing for acquisition was three times the water depth, and data was retained out to 60 or 70 degrees from nadir, depending on project area. Heave, roll, pitch and heading correctors were collected using an Applanix POS/MV Model 320 inertial measurement unit (IMU) and associated Trimble GPS antennas. Sound velocity profiles were acquired with a Seabird Electronics SeaCat SBE19P CTD profiler and processed using Seabird Seaterm software, then applied directly to the raw GSF data. Positioning was obtained using Northstar 941X GPS receivers with differential correctors from U.S. Coast Guard CORS beacon Isabel, Puerto Rico. Data was reduced to Mean Lower-Low Water (MLLW) using final approved tides from NOAA COOPS, based on National Water Level Observation Network (NWLON) primary tide stations at Charlotte Amalie, VI (9751639) and Lime Tree Bay, VI (9751401).
For the 2005 project, raw SWMB data in GSF (generic sensor format) format were converted and processed using CARIS HIPS v5.4 software, resulting in a CARIS HDCS format dataset with all correctors applied. Attitude and SWMB data was cleaned of fliers, and SWMB data was reviewed in subset mode by a NOAA contractor.