Summary

Description

This image represents a 0.5 meter resolution backscatter mosaic of Grammanik Bank, south of St. Thomas, 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 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 WGS84. The backscatter component of the bathymetry data were processed by the Hawaii Mapping Research Group (HMRG), University of Hawaii using the HAWAII MR1 Sidescan Sonar Software Suite. The data were corrected for angle varying gain, transmit power and pulse width. Electronic and acoustic noise, such as striping due to across track variations in amplitude and speckling due to transducer motion, were removed.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.