New York Bight and Gulf of Maine bathymetric contours (NY_GOME_CONTOURS)

The desired data was extracted from the Coastal Relief Model volumes 1 & 2 in the ESRI ASCII grid format

The retrieved data was combined to create a PCI Remote Sensing image database and stored in a 16-bit image channel.

The CRM PCI database was processed to extract a subset of the combined dataset. A 5X5 low-pass smoothing filter was applied to the image data to reduce the gridding artifacts.

Two additional 16 bit channels were added to the newly created PCI database containing the data subset. The CRM data was processed to create separate land and sea image channels by replacing the values above and below the desired data level with -32768.

An image mask of the bathymetry data was created. The XPACE CONTOUR program was run on the CRM data to create a 100m contour segment of the original data. The CRM image was then subsetted to create a bathymetry image with values between 11-200 meters and contoured at 10m. The created contours were then thinned by 50% (VECSEL).

All contours greater than 200 m were removed from the 10 m contour segment to remove redundancy of the 100 m contours before combining the 10 m and 100 m contours as one segment.

The bathymetry contours were viewed and edited using Imageworks to verify and improve the dataset. Small contours that were believed to be artifacts of the CRM gridded data were removed. Vector segments that could be combined to produce complete polylines were joined.

The final bathymetry contours were exported from the PCI database to an ArcView shapefile.

The shapefile was projected from the original WGS84 to NAD83/GRS_1980 for consistency with other datasets.

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. Added a landing page link as the first link in the identification section. The source information was incomplete and had to be modified to meet the standard. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. Added the online link to the data in the distribution section. 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.