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AFSC/RACE/GAP/Zimmermann: Central Gulf of Alaska Grid

Metadata Updated: April 1, 2024

We assembled 1.75 million National Ocean Service (NOS) bathymetric soundings from 225 lead-line and single-beam echosounder hydrographic surveys conducted from 1901 to 1999 in the central Gulf of 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 Our editing included deleting erroneous and superseded values, digitizing missing values, and properly aligning all data sets to a common, modern datum. There were several areas where these older surveys were superseded by more recent, higher quality multibeam surveys, mostly from the NOS (n=106). Three of these were unprocessed NOS multibeam surveys in the Sitka area, which we edited and processed into final bathymetric surfaces. We reduced the resolution of these multibeam surveys to 100 m, since some may have sub-meter resolution and many exceed a million soundings, and added them to our bathymetry compilation. We proofed, edited or digitized 96,000 cartographic features (mostly from the smooth sheets, some from the multibeam surveys), such as rocky reefs, kelp beds, rocks and islets, creating the most thorough source of these typically shallow, inshore features. The depth surface and inshore features, available at the Alaska Fisheries Science Center (AFSC: http://www.afsc.noaa.gov), were mostly produced at a map scale of 1:20,000.

Access & Use Information

License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

Downloads & Resources

Dates

Metadata Date February 29, 2024
Metadata Created Date October 28, 2022
Metadata Updated Date April 1, 2024
Reference Date(s) 2015 (publication)
Frequency Of Update notPlanned

Metadata Source

Harvested from NMFS AFSC

Additional Metadata

Resource Type Dataset
Metadata Date February 29, 2024
Metadata Created Date October 28, 2022
Metadata Updated Date April 1, 2024
Reference Date(s) 2015 (publication)
Responsible Party (Point of Contact, Custodian)
Contact Email
Guid gov.noaa.nmfs.inport:22897
Access Constraints Cite As: Alaska Fisheries Science Center, [Date of Access]: AFSC/RACE/GAP/Zimmermann: Central Gulf of Alaska Grid [Data Date Range], https://www.fisheries.noaa.gov/inport/item/22897., Access Constraints: These data are not to be used for navigation., Use Constraints: These data are not to be used for navigation. As more bathymetry data becomes available, and as more time allows, additional bathymetry drafts will be completed. Our slow method of data editing and compilation, which relied on comparing the digitized soundings to the smooth sheets in a GIS, was critical to the discovery and elimination of numerous errors, such as incorrect, misplaced and missing soundings. Properly accounting for the horizontal shift from the original datum to NAD 1983 HARN was the most important part of our error-checking. We consider this smooth sheet bathymetry and feature compilation a first draft.
Bbox East Long -134.2
Bbox North Lat 60.7
Bbox South Lat 53.9
Bbox West Long -154.6
Coupled Resource
Frequency Of Update notPlanned
Harvest Object Id b06c2e6a-dc8a-4c3f-8778-ade8757424cf
Harvest Source Id 26a29bb9-50b0-47fd-920b-edc74aa6ec76
Harvest Source Title NMFS AFSC
Licence NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose.
Lineage unknown
Metadata Language eng
Metadata Type geospatial
Old Spatial {"type": "Polygon", "coordinates": [[[-154.6, 53.9], [-134.2, 53.9], [-134.2, 60.7], [-154.6, 60.7], [-154.6, 53.9]]]}
Progress completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 1901
Temporal Extent End 1999

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