Coastal Bathymetry Data Collected in 2016 from the Chandeleur Islands, Louisiana–Interpolated Digital Elevation Model
The U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS SPCMSC), collected single beam and swath bathymetry data from the northern Chandeleur Islands, Louisiana, in June of 2016. This USGS data release includes the resulting processed elevation point data (xyz) and an interpolated digital elevation model (DEM).
This USGS data release provides 437-line kilometers (km) of processed single beam bathymetry (SBB) and interferometric bathymetry (IFB) data collected under Field Activity Number (FAN) 2016-335-FA. This FAN encompasses two subfans each of which represents one survey vessel; the research vessel (RV) Sallenger (subFAN 16BIM01) collected IFB data and the RV Jabba Jaw (subFAN 16BIM02) acquired SB) data. SBB and IFB point data (xyz) are provided in two datums; the International Terrestrial Reference Frame of 2008 (ITRF08) and ellipsoid height and the North American Datum of 1983 (NAD83) in the CORS96 realization for the horizontal and the North American Vertical Datum of 1988 (NAVD88), using the geoid model of 2009 (GEOID09), orthometric height for the vertical. Additional files provided in this data release include: trackline shapefiles, digital and handwritten field logs, and a comprehensive 50-meter (m) DEM. For additional information regarding data collection and processing of the sounding data, please refer to the field logs and formal Federal Geographic Data Committee (FGDC) metadata for the individual IFB and SBB point data (xyz) files and survey trackline shapefiles also included within this publication and available at,
https://doi.org/10.5066/P993MBJK.
Chandeleur_Islands_2016_SBB_and_IFB_
NAD83_NAVD88_GEOID09_50_DEM.tif was derived from the processed swath data are provided as American Standard Code for Information Interchange (ASCII) xyz point data files. These values are not the individual soundings, they are the exported BASE (Bathymetry with Associated Statistical Error) surface at 5-m spatial distances with associated CUBE (Combined Uncertainty and Bathymetry Estimator) sample surface created from the edited soundings dataset using CARIS HIPS and SIPS version 9.1. These are considered interpolated samples in which one value represents all soundings within a five-meter node, weighted by uncertainty and proximity, giving the final value as a data sample within the specific grid cell.
The swath bathymetry data were collected and processed in the World Geodetic System of 1984 (WGS84[1762]) datum, which is equivalent ITRF08. This dataset was transformed from ITRF08 to the NAD83 geodetic datum and NAVD88 orthometric height, using the GEOID09 with the National Oceanic and Atmospheric Administration (NOAA) VDatum version 3.6 transformation software (
http://vdatum.noaa.gov/).
The single beam surveys were acquired and processed to a geodetic reference ellipsoid. The single beam data were collected using stand-alone GPS and then post-processed to obtain Differential Global Positioning System (DGPS) navigation. All single beam surveys were collected in WGS84 (G1150), which is equivalent to the International Terrestrial Reference Frame of 2000 (ITRF00). This dataset was transformed from ITRF00 to both ITRF08 and the NAD83 geodetic datum with NAVD88 orthometric height, using the GEOID09 model via NOAA’s VDatum software. The final NAD83/NAVD88 GEOID09 SBB and IFB x,y,z position data from this survey were merged to generate a single point file that was subsequently used to create the interpolated DEM, Chandeleur_Islands_2016_SBB_and_IFB_
NAD83_NAVD88_GEOID09_50_DEM.tif.
