Esri Binary 2-m Bathymetric Grid of National Oceanic and Atmospheric Administration (NOAA) Survey H12298 in Block Island Sound (UTM Zone 19, NAD 83, H12298_2M_UTM)

Bathymetric data were acquired in extended Triton data format (XTF) and recorded digitally through an ISIS data acquisition system. A RESON SeaBat 7125 multibeam echosounder, with a frequency of 400 kHz, was used to collect MBES data on the Thomas Jefferson and both survey launches. 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 and a subordinate gauge at Orient Harbor, NY. The vertical resolution of the multibeam data is approximately 0.5% of the water depth. Vertical datum is mean lower low water; X and Y units are meters; UTM Zone 19, NAD 83.

The field sheets from the survey (average depths, not the shoal based field sheets) were read back into CARIS HIPS/SIPS software version 8.1 and combined into a single field sheet with a 2-meter cell size using the BASE surface combine tool in CARIS. This process step and all subsequent steps were performed by the same person, William Danforth.

A base surface was then exported from CARIS as an Esri ASCII raster grid. The ASCII raster file was converted to a binary Esri grid using the ASCII to raster tool in ArcGIS v10.0, SP2 (ArcToolbox, Conversion Tools, To Raster, ASCII to Raster), retaining the grid cell size (2 meter node spacing). The projection information (NAD_1983_UTM_Zone_19N) was then written to the binary grid using the Define Projection tool (ArcToolbox, Data Management Tools, Projections and Transformations).

Edits to the metadata were made to fix any errors that MP v 2.9.36 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.). Attempted to modify http to https where appropriate. The source information was incomplete and had to be modified to meet the standard. Updated the link to the field activity. 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.