Data Management Plan

This image represents a 3 meter resolution backscatter mosaic of the north shore of St. Croix, US Virgin Islands. 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 3/21/06 to 4/2/06. Data was acquired with a hull-mounted Kongsberg Simrad EM 1002 multibeam echosounder (95 kHz) and processed by a NOAA contractor using CARIS HIPS 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 WGS84. The backscatter component of the bathymetry data were geometrically and radiometrically corrected using Geocoder 2.8 software. Acoustic backscatter mosaics are ostensibly an important piece of information when characterizing surficial seafloor features and delineating benthic habitats. The project was 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.

Process Steps:

• 2006-01-01 00:00:00 - For this 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 3/21/06 to 4/5/06, as project number NF-06-03. Multibeam data was acquired in Simrad .all format with a hull-mounted Kongsberg Simrad EM 1002 multibeam echosounder (95 kHz). Simrad backscatter snippet collection was enabled. Line spacing for acquisition was three times the water depth, and data was retained out to 60 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. 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). | Source Produced: NF-06-03 Raw Multibeam Data (Citation: NF-06-03 Raw Multibeam Data)
• 2006-01-01 00:00:00 - Raw SWMB data were converted and processed using CARIS HIPS v6.0 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. (Citation: NF-06-03 HDCS Processed Multibeam Data)
• 2006-10-01 00:00:00 - The multibeam backscatter data were corrected for geometric and radiometric distortions using Geocoder 2.8. In particular, the following corrections were applied where appropriate and when artifacts were evident: AVG Trend, TX Power and RX Gain, Area Correction, Spreading, Slant-Range and Extracted Beam Pattern. As no theoretical beam pattern for the Kongsberg Simrad 1002 system exists, it was extracted from a mapped area that was flat and had a relatively uniform (sandy) substrate. Individual lines were also truncated based on ping number and/or angle of incidence where appropriate. The final mosaics were exported as geotiffs in WGS 1984 UTM Zone 20N and Backscatter values as measured in decibels dBs. | Source Produced: Backscatter_Buck_Island_2006.tif (Citation: NF-06-03 HDCS Processed Multibeam Data)