Esri Binary 2-m Bathymetric Grid of National Oceanic and Atmospheric Administration (NOAA) Survey H12023 in Block Island Sound (H12023_2M_UTM, UTM Zone 19, NAD83)

Bathymetric data were acquired in extended Triton data format (XTF) and recorded digitally through an ISIS data acquisition system. A RESON 7125, hull-mounted on the NOAA ship Thomas Jefferson and one 8.5-m launch and a RESON 8125 multibeam echosounder, mounted on another 8.5-m launch deployed from the NOAA ship Thomas Jefferson, were used to acquire the sounding data. All positioning and attitude were determined with Trimble DSM212L DGPS receivers and Applanix POS/MV Model 320 v.4 inertial navigation systems. The data were processed using CARIS HIPS (Hydrographic Image Processing System) software for quality control, and to incorporate sound velocity and tidal corrections. Sound velocity corrections were derived using frequent SEACAT CTD (conductivity-temperature-depth) profiles. Typically, a CTD cast was conducted every three to four hours of multibeam acquisition. Tidal zone corrections were calculated from data acquired at the Newport, Rhode Island, New London, Connecticut, and Montauk, New York tidal gauges. The vertical resolution of the multibeam data is approximately 0.5% of the water depth. The data were gridded to 2-m resolution and saved as a CARIS HIPS database. Vertical datum is mean lower low water; X and Y units are meters; UTM Zone 19, NAD83.

Using CARIS v7.1.1: Opened the 2m fieldsheet provided by NOAA NOS (H12023_combined_2m). Exported to Bathymetric Attributed Grid (BAG) file (H12023_combined_2m.bag)

Imported BAG surface H12023_combined_2m.bag and converted to SD file H12023_combined_2m.sd using IVS DMagic 7.3.1a.

Exported to ArcView Grid (H12023_combined_2m.asc) using IVS DMagic 7.3.1a.

Converted ArcView Grid (H12023_combined_2m.asc) to Esri 32-bit floating point Grid (h12023_2m_utm). [ArcToolbox - Conversion Tools - To Raster - ASCII to Raster] using ArcCatalog 9.3.

Defined projection for grid h12023_2m_utm as NAD83 UTM zone 19. [ArcToolbox - Data Management Tools - Projections and Transformations - Define Projection] using ArcCatalog 9.3.

Edits to the metadata were made to fix any errors that MP v 2.9.32 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent.

Added keywords section with USGS persistent identifier as theme keyword.