gov.noaa.nmfs.inport:22897 eng UTF8 dataset Alaska Fisheries Science Center 7600 Sand Point Way N.E., Building 4 Seattle WA 98115 USA https://www.afsc.noaa.gov WWW:LINK-1.0-http--link Website Website for this organization information 0700-1700 Pacific Time resourceProvider Zimmermann, Mark mark.zimmermann@noaa.gov pointOfContact 2026-03-04T19:17:17 ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for imagery and gridded data ISO 19115-2:2009(E) AFSC/RACE/GAP/Zimmermann: Central Gulf of Alaska Grid AFSC/RACE/GAP/Zimmermann: Central Gulf of Alaska Grid 2015 publication NOAA/NMFS/EDM 22897 https://www.fisheries.noaa.gov/inport/item/22897 WWW:LINK-1.0-http--link Full Metadata Record View the complete metadata record on InPort for more information about this dataset. information Zimmermann, Mark mark.zimmermann@noaa.gov originator https://www.afsc.noaa.gov/RACE/groundfish/bathymetry/CGOA_bathymetry_grid.zip WWW:LINK-1.0-http--link Citation URL Online Resource download mapDigital 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 Our editing included deleting erroneous and superseded values, digitizing missing values, and properly aligning all data sets to a common, modern datum. There were several areas where these older surveys were superseded by more recent, higher quality multibeam surveys, mostly from the NOS (n=106).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. The purpose for creating this data set was to provide the best available bathymetry and inshore features of the central Gulf of Alaska for predictive, geospatial modeling of marine resources. These bathymetry data were proofed, edited and digitized by Mark Zimmermann and Megan Prescott. Funding for much of the work was provided by NOAA's Essential Fish Habitat (EFH), Habitat and Ecological Processes Research (HEPR) through the Alaska NMFS Regional Office. B. McMahon, G. Nelson (retired) and especially C. Barry (Pacific Hydrographic Branch of the NOS) provided assistance with interpreting smooth sheets, bathymetric sounding files, and descriptive reports. D. Doyle and J. Benson provided valuable datum and GIS advice, respectively. D. Fischman, G. Glover, J.A. Bunn, J. Campagnoli, M. Frydrych, and M. Cole from the National Geophysical Data Center helped with accessing smooth sheets on the NGDC web site. completed Zimmermann, Mark mark.zimmermann@noaa.gov pointOfContact Zimmermann, Mark mark.zimmermann@noaa.gov custodian notPlanned Alaska Cook Inlet North Pacific Ocean bathymetry grid theme DOC/NOAA/NMFS/AFSC > Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, U.S. Department of Commerce dataCentre Global Change Master Directory (GCMD) Data Center Keywords 2017-04-24 publication 8.5 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 22. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian Groundfish Assessment Program project InPort otherRestrictions 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. 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. otherRestrictions Access Constraints: These data are not to be used for navigation. otherRestrictions 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. unclassified NOAA Data Management Plan (DMP) NOAA/NMFS/EDM 22897 https://www.fisheries.noaa.gov/inportserve/waf/noaa/nmfs/afsc/dmp/pdf/22897.pdf WWW:LINK-1.0-http--link NOAA Data Management Plan (DMP) NOAA Data Management Plan for this record on InPort. information crossReference eng; US elevation imageryBaseMapsEarthCover oceans Microsoft Windows 7 Version 6.1 (Build 7600) ; ESRI ArcGIS 10.0.5.4400 -154.6 -134.2 53.9 60.7 | Currentness: observed 1901 1999 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, 106 multibeam data sets were subsetted at a resolution of 100 m and substituted for the older, less-detailed smooth sheet data. Third, the bathymetry point data, which included bathymetric soundings, inshore features with depths or elevations, and the reduced-resolution multibeam data, 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 to cover the spatial extent of the study area. Alaska Fisheries Science Center (206) 526-4000 (206) 526-4004 7600 Sand Point Way N.E., Building 4 Seattle WA 98115 USA afsc.webmaster@noaa.gov https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center WWW:LINK-1.0-http--link Alaska Fisheries Science Center Website AKFSC Home Page information 0700-1700 Pacific Time distributor https://www.ncei.noaa.gov WWW:LINK-1.0-http--link https://www.ncei.noaa.gov download https://www.afsc.noaa.gov/RACE/groundfish/bathymetry/CGOA_bathymetry_grid.zip WWW:LINK-1.0-http--link https://www.afsc.noaa.gov/RACE/groundfish/bathymetry/CGOA_bathymetry_grid.zip download dataset Completeness Report Our editing included deleting erroneous and superseded values, digitizing missing values, and properly aligning all data sets to a common, modern datum. Conceptual Consistency not applicable unknown otherRestrictions Use Constraints: These data are not to be used for navigation.