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AFSC/RACE/GAP/Zimmermann: Cook Inlet Bathymetry Features
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We assembled 1.4 million National Ocean Service (NOS) bathymetric soundings from 98
lead-line and single-beam echosounder hydrographic surveys conducted from 1910 to
1999 in Cook Inlet, 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 Our editing included deleting erroneous and superseded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. There were six areas where these older surveys were superseded by compilations
of reduced-resolution multibeam surveys. We digitized 12,000 features, such as rocky
reefs, kelp beds, rocks and islets, adding them to what was originally available,
and creating the most thorough source (n = 18,000) of these typically shallow, inshore
features. We also digitized 2,418 km of the mainland and 529 km of island shoreline,
generally at a resolution of 1:20,000, and digitized 9,271 verbal surficial sediment
descriptions from the smooth sheets. The depth surface, shoreline, inshore features,
and sediment data sets are mostly produced at a scale of 1:20,000.
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