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AFSC/RACE/GAP/Prescott: Norton Sound Bathymetry
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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and superseded values, digitizing missing values, and properly aligning all data sets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.
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