AFSC/RACE/GAP/Prescott: Norton Sound Bathymetry

We assembled approximately 230,000 National Ocean Service (NOS) bathymetric soundings from 39 lead-line and single-beam echosounder hydrographic surveys conducted from 1896 to 2005 in Norton Sound, Alaska. These bathymetry data are available from the National Geophysical Data Center (NGDC: http://www.ngdc.noaa.gov), which archives and distributes data that were originally collected by the NOS and others. While various bathymetry data have been downloaded previously from NGDC, compiled, and used for a variety of projects, our effort differed in that we compared and corrected the digital bathymetry by studying the original analog source documents - digital versions of the original survey maps, called smooth sheets. Our editing included deleting erroneous and superseded values, digitizing missing values, and properly aligning all data sets to a common, modern datum. We incorporated 3 multibeam surveys, and added an additional 6,992 single-beam soundings from the 2010 Northern Bering Sea bottom trawl survey to fill in where smooth sheet data was lacking. We proofed and digitized 312 cartographic features, comprised mostly of rocks and islets and also digitized 4,305 verbal sediment descriptors, and digitized or adapted 2,142 km of mainland and 837 km of island shoreline.

The purpose for creating this data set was to provide the best available bathymetry and inshore features of Norton Sound for predictive, geospatial modeling of marine resources.

Loaded by FGDC Metadata Uploader, batch 5766, 04-06-2015 12:50

The following FGDC sections are not currently supported in InPort, but were preserved and will be included in the FGDC export:

- Spatial Reference Information (FGDC:spref),

- Spatial Data Organization Information (FGDC:spdoinfo)

- Lineage (FGDC:lineage)

This bathymetry grid was created in several steps. First, the bathymetry point data and inshore smooth sheet features, such as rocks and islets, were compared to the source documents - the smooth sheets - and corrected or digitized. Second, single-beam echobeam data was added to fill in gaps in the smooth sheet coverage. Multibeam surveys were then added, supercededing older smooth sheet data. These data points then combined with shoreline data points and were used to create a Triangulated Irregular Network (TIN). The TIN was converted into a grid (raster with 100 meter square pixels). Finally, the grid was trimmed by the shoreline, removing any points that fell on land.

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These data are not to be used for navigation.

These data are not to be used for navigation. These data are not to be used for navigation. We consider this smooth sheet bathymetry, feature, shoreline, and sediment compilation a fairly complete first draft.

These data are not to be used for navigation.

Microsoft Windows 7 Version 6.1 (Build 7600) ; ESRI ArcGIS 10.2.2

Our editing included deleting erroneous and superseded values, digitizing missing values, and properly aligning all data sets to a common, modern datum.

not applicable

Our editing included deleting erroneous and superseded values, digitizing missing values, and properly aligning all data sets to a common, modern datum.

IT Security and Contingency Plan for the system establishes procedures and applies to the functions, operations, and resources necessary to recover and restore data as hosted in the Western Regional Support Center in Seattle, Washington, following a disruption.

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