Color Shaded-Relief GeoTIFF Image Showing the Bathymetry Generated from National Oceanic and Atmospheric Administration (NOAA) Survey H12324 in Narragansett Bay (UTM Zone 19, NAD 83)

Multibeam-echosounder (MBES) data were collected aboard the 30-foot NOAA Survey Vessel S3002, using a hull-mounted Kongsberg Simrad EM3002. This system has a 130-degree swath width and a maximum ping rate of 40 Hz. Positioning was determined by differential global positioning system (DGPS) which received corrections from Acushnet, Massachusetts. Water levels are mean lower low water and were corrected for tides using National Water Level Observation Network stations in Newport, Rhode Island, and Quonset Point, R.I. MBES data were processed (tide correction, merging with navigation data, TPU calculation, data cleaning, and CUBE BASE surface creation) using Computer Aided Resource Information System (CARIS) Hydrographic Information Processing System (HIPS) software. Bathymetric Attributed Grid (BAG) files were uploaded to the National Geophysical Data Center (NGDC). Vertical datum is mean lower low water; X and Y units are meters; UTM Zone 19, NAD 83.

BAG files of 1-m, 2-m, and 4-m resolution (1-m resolution covers 0-20 m depth, 2-m resolution covers 18-40 m depth, and 4-m resolution covers 36-80 m depth) were opened in Global Mapper v. 14.1. Image was hillshaded at 45-degrees altitude and azimuth, and vertically exaggerated 3x. Projection was UTM Zone 19, NAD 83. A GeoTIFF was exported with 1-m resolution (this supersamples the data collected at 2- and 4-m resolution, it does not improve the resolution), to preserve the high-resolution of shallow areas (File, Export, Raster/Image Format, GeoTIFF). Export options are a 24-bit image, default resampling, default resolution (just shy of 1-m), default compression, and a TFW (world) file was created.

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 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.