Summary

Description

This dataset contains an ESRI Grid representing the slope (in degrees) of the bathymetry of the north shore of St. Croix, US Virgin Islands, based on a 3 m bathymetric grid. 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 v6.0 software. Data has all correctors applied (attitude, sound velocity) and has been reduced to mean lower low water (MLLW) using final approved tides and zoning 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. An ASCII XYZ file was exported from the BASE surface and opened in ESRI ArcMap 9.1 as an XY event. Then the ArcToolbox conversion tool 'Feature to Raster' was used to generate an ESRI Grid of bathymetry. Finally, the Slope calculator within ArcGIS Spatial Analyst/Surface Analysis was used to calculate slope in degrees, using that ESRI Grid of source bathymetry. 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.