Interpretation of the thickness of Quaternary deposits on the inner-continental shelf within the New York Bight, derived from seismic data collected by the U.S. Geological Survey, 1995 - 1999 (Grid, UTM Zone 18N, WGS84 and Esri polyline shapefile, Geographic, WGS84)

Processed SEG-Y seismic data and associated shot navigation data were loaded into Landmark Seisworks interpretation software. The coastal-plain unconformity was digitized along with the seafloor reflector. The difference in two-way travel time between horizons was calculated and converted to meters using an assumed velocity of 1630 m/s. This represents the nearshore Quaternary sediment thickness. These data were exported from seisworks to an ASCII format file.

The ASCII point data were imported to Dynamic Graphics Inc., EarthVision surface modelling software. The points representing Quaternary sediment thickness were gridded with a 200 meter grid cell size. Bathymetric data that were collected the same time as the seismic profile data were gridded using a 150 m grid cell size. The Quaternary sediment thickness grid was addded to the bathymetric grid to yield a grid for the nearshore elevation of the Coastal plain unconformity reference to mean sea water. This grid was exported as an ASCII format file.

The exported ASCII file from the nearshore coastal-plain unconformity elevation was combined with onshore well elevations of the coastal-plain unconformity.

The total onshore and nearshore coastal-plain unconformity elevations were imported into EarthVision. The data were gridded at a 200 m grid spacing.

The grid of the elevation of Coastal plain unconformity was merged with the grid of the elevation of Coastal plain unconformity (cp_elev within source information) generated for the nearshore offshore of southern Long Island within EarthVision by using the union command. Minor edits were necessary along the boundaries of the point of union.

The Quaternary thickness grid was calculated by taking the difference between the coastal-plain unconformity grid and the coastal releif model. The Quaternary thickness grid was exported as an ASCII file.

The exported ASCII Quaternary sediment thickness grid file from EarthVision was edited to create an ASCII grid file suitable for import to ArcView software. The order of rows were flipped, so that the file begins with the lower row, left column and ends with the upper row right column. An ArcView header that descibes the lower left origin of the grid, the grid cell size, the number of rows and columns, and the null value used (-9999).

The edited ASCII grid file was imported into ArcView software with the 3D Spatial Analyst extension. The file was saved as an ArcInfo raster grid format.

Contour data were generated from the Quaternary Isopach Gridded data at a 5 meter contour interval within EarthVision. These data were exported and converted to an ESRI generate format. The contour interval associated with each contour was saved as an ASCII file and read into ArcView in table format. The generate file was converted to a vector shapefile. The table and attritube table of the contour shapefile were joined based on unique contour IDs. The attribute table was then editted to include the associated contour value with each contour line, and the join was removed.

The grid and contour data were clipped, using the GRIDCLIP script within ArcView 3.2, to the extents of the 1995 and 1996 survey areas.

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.). Completely changed the title based on an author (Jane Denny) supplied title. Added online links to the publication and data page in the Identification section. Added the standard order section to the Distribution Information, which included providing a link to download the data. The metadata describes both the grid and the contours, but the contours are the only dataset available for download in a zip file from the publication. Downloading the grid would require downloading individual files within folders. 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.