Bathymetric Map of the Bering/Chukchi Sea

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Frequently anticipated questions:

What does this data set describe?

Title: Bathymetric Map of the Bering/Chukchi Sea
Abstract:
Two bathymetric maps were developed by the U.S. Geological Survey, one for the Chukchi Sea and Arctic Ocean, and one for the Aleutian Trench and Bering Sea. The 2 maps overlap near the Bering Strait. Bathymetric contours were generated from several published sources. It is unclear whether new soundings were collected for these maps. The northern map extends from Wrangel Island, Russia to MacKenzie Bay, Canada, and north to 76 N latitude. The southern map extends from Shelikof Bay, Russia, to the western tip of the Alaska Peninsula, USA, and south to 48 N latitude. Bathymetric contours are at 400 meter intervals with 20, 30, 40, 50, 100, and 200 meter contours added. Contours above 50 meters are rare, and never along the Russian coast. Hard-copy maps were published by the USGS in 1976 and digitized by the Alaska Science Center in 1997. In digital format, the 2 maps have been connected where they overlap in the Bering Strait.
Supplemental_Information:
The USGS Alaska Science Center created this and other digital bathymetry coverages to support marine animal research in the Bering and Chukchi Seas. The completed coverages are being stored on the Coastal and Marine Geoscience Data System (CMGDS) for archival purposes only. The coverage "Bathymetric Map of the Bering/Chukchi Sea" is titled BERCHUK_3GEO (ber=bering sea, chuk=chukchi sea, 3=polygon topology, geo=geographic projection)
  1. How might this data set be cited?
    U.S. Geological Survey, 19970430, Bathymetric Map of the Bering/Chukchi Sea: U.S. Geological Survey, Anchorage, Alaska.

    Online Links:

    Other_Citation_Details:
    Citation of the source map: Schumacher, G. M. 1976. Bathymetric map of the Chukchi Sea and Arctic Ocean. USGS Open-File Report 76-823. Schumacher, G. M. 1976. Bathymetric map of the Aleutian Trench and Bering Sea. USGS Open-File Report 76-821.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: 154
    East_Bounding_Coordinate: -130
    North_Bounding_Coordinate: 76
    South_Bounding_Coordinate: 48
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 1976
    Currentness_Reference:
    map publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference: Bathymetric contours
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • String (5380)
      • Entity point (460)
      • GT-polygon composed of chains (461)
      • Entity point (11)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 4.1101378883467987e-005. Longitudes are given to the nearest 4.1101378883467987e-005. Latitude and longitude values are specified in Decimal Degrees. The horizontal datum used is D Clarke 1866.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.9786982.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: No correction
      Depth_Resolution: 400
      Depth_Distance_Units: meters; 10m, 50m, and 400m contours are represented
      Depth_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    berchuk_3geo.aat
    Bathymetric Map of the Bering/Chukchi Sea Arc Attribute Table (arcs) (Source: USGS; ESRI)
    FID
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    FNODE#
    Internal node number for the beginning of an arc (from-node). (Source: ESRI) Whole numbers that are automatically generated.
    TNODE#
    Internal node number for the end of an arc (to-node). (Source: ESRI) Whole numbers that are automatically generated.
    LPOLY#
    Internal node number for the left polygon. (Source: ESRI) Whole numbers that are automatically generated.
    RPOLY#
    Internal node number for the right polygon. (Source: ESRI) Whole numbers that are automatically generated.
    LENGTH
    Length of feature in internal units. (Source: ESRI) Positive real numbers that are automatically generated.
    BERCHUK#
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    BERCHUK-ID
    User-defined feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    DEPTH
    Depth in meters below sea level for each contour. (Source: USGS)
    Range of values
    Minimum:20
    Maximum:8000
    Units:meters
    CLASS
    A categorical variable to define the line type. (Source: USGS) Class=0 for digitized bathymetric contours; class=8 for arcs that were added to close polygons; and class=9 for the Russian and US/Canadian coastlines. There were 2 cases where class 8 arcs were used: (1) when contours ended because adjoining contours were too close, and (2) the box used as the perimeter of the coverage.
    berchuk_3geo.pat
    Bathymetric Map of the Bering/Chukchi Sea Polygon Attribute Table (polygons) (Source: USGS; ESRI)
    FID
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    AREA
    Area of feature in internal units squared. (Source: ESRI) Positive real numbers that are automatically generated.
    PERIMETER
    Perimeter of feature in internal units. (Source: ESRI) Positive real numbers that are automatically generated.
    BERCHUK#
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    BERCHUK-ID
    User-defined feature number. (Source: ESRI) Sequential unique whole numbers that were automatically generated.
    MID_DEPTH
    Polygon attribute calculated as the mid-point between bounding arcs, e.g. mid-depth between 50 and 100 meter contours equals 75 meters, and between 4,000 and 4,400 meter contours is 4,200 meters. Where a bathymetric contour was an "island" and there was no further depth information inside the "island", the mid-depth was coded as the bounding contour's depth. (Source: USGS)
    Range of values
    Minimum:25
    Maximum:8000
    Entity_and_Attribute_Overview:
    The coverage contains two attributes pertinent for data analysis and display (depth and mid-depth, and one attribute that specifies the line type (class). Depth is an arc attribute (.aat) that specifies the ocean depth at each contour in meters. Mid-depth is a polygon attribute (.pat) calculated from the depth values of each polygon's bounding contours (e.g. a polygon with bounding contours of 30 m and 40 m would be 35 m). Class displays the type of line, 0 for digitized contours, 9 for the coastline, and 8 for arcs added to close polygons.
    Entity_and_Attribute_Detail_Citation: Producer

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Alaska Science Center, Marine and Fresh Water Ecology Branch
    Biological Resources Division, U.S. Geological Survey
    Anchorage, Alaska
    USA

    907-786-3512 (voice)
    907-786-3636 (FAX)
    Hours_of_Service: 8:00 am to 4:00pm Monday through Friday
    Contact_Instructions: None

Why was the data set created?

The maps were produced to aid in geophysical research and exploration in the Bering and Chukchi Seas.

How was the data set created?

  1. From what previous works were the data drawn?
    USGS_berchuk (source 1 of 1)
    U.S. Geological Survey, 1976, Bathymetric map of the Chukchi Sea and Arctic Ocean.: Open-File Report 76-821 and 76-823, U.S. Geological Survey, Washington, D.C..

    Other_Citation_Details:
    Schumacher, G.M., 1976, Bathymetric map of the Chukchi Sea and Arctic Ocean: USGS Open-File Report 76-823. -and- Schumacher, G.M. 1976, Bathymetric map of the Aleutian Trench and Bering Sea: USGS Open-File Report 76-821.
    Type_of_Source_Media: Map
    Source_Contribution:
    The map provided the bathymetric contours for the digitized vector data
  2. How were the data generated, processed, and modified?
    Date: Sep-1996 (process 1 of 4)
    Two separate tic bases were created in Arc/INFO using the generate command with the fishnet option for each map area. The tic bases were projected from geographic to Albers Equal Area (projection of the source maps) and used to register maps for digitizing. Central merideans were located from the source maps' author as -158 for 76-823 and 175 for 76-821. Arcs were hand digitized. The digitized version of 76-823 was projected to a central meridian of 175 to match 76-821 and the maps were appended together. A problem a\occurred with the Arc/INFO software when trying to project across 180 degrees. Arcs that straddled 180 were clipped and had to be manually snapped together. This will be a problem whenever this coverage is reprojected until Arc/INFO resolves the problem in the software. After the map was digitized and projected into geographic, the digital chart of the world coastline (1:2,000,000 scale) was added to provide a land reference and complete the near shore polygons. Processing tolerances were: weed 40 m, grain 40 m, dangle 0.1 m, and fuzzy 0.1 m. Note that the tolerances are listed in meters and the coverage is in geographic. THESE TOLERANCES SHOULD BE SPECIFIED IN ANY FUTURE CLEAN TO MAINTAIN THE INTEGRITY OF THE COVERAGE. Person who carried out this activity:
    Alaska Science Center, Marine and Fresh Water Ecology Branch
    Biological Resources Division, U.S. Geological Survey
    Anchorage, Alaska
    USA

    907-786-3512 (voice)
    907-786-3636 (FAX)
    Hours_of_Service: 8:00 am to 4:00pm Monday through Friday
    Contact_Instructions: None
    Data sources used in this process:
    • USGS_berchuk
    Date: 14-Feb-2017 (process 2 of 4)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 19-Oct-2020 (process 3 of 4)
    Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 18-Nov-2021 (process 4 of 4)
    Edited metadata to fix validation errors and to bring it up to FGDC CSDGM current standards based on data release policies for USGS Coastal and Marine Hazards and Resources Program (CMHRP). No data were changed. The metadata available from a harvester may supersede metadata bundled within a download file. Users are advised to compare the metadata dates to determine which metadata file is most recent. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Susan Cochran
    Geologist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7545 (voice)
    scochran@usgs.gov
  3. What similar or related data should the user be aware of?
    Service, National Ocean, and U.S. Department of Commerce, Unknown, Coastal Shelf Bathymetry of the Bering, Chukchi, and Beaufort Seas: Department of Commerce, NOAA, NOS, Washington, D.C..

    Other_Citation_Details:
    Bathymetric maps available for purchase from National Geophysical Data Center, E/GC3, 325 Broadway, Boulder, Colorado 80303-3228.
    U.S. Geological Survey, 1976, Plate 1. Topographic and Bathymetric Map of the Northern Bering Sea Region: U.S. Geological Survey Professional Paper 759-B, U.S. Government Printing Office, Washington, D.C..

    Other_Citation_Details:
    Hopkins, D.M., Nelson, C.H., Perry, R.B., and Alpha, T.R., 1976, Physiographic subdivisions of the Chirikov Basin, Northern Bering Sea (studies on the marine geology of the Bering Sea): Geological Survey Professional Paper 759-B, U.S. Government Printing Office, 7 pp, 3 plates.
    U.S. Geological Survey, 1984, Bathymetric map of the Chukchi Sea: Miscellaneous Investigations Series Map I-1182-D, U.S. Geological Survey, Washington, D.C..

    Other_Citation_Details:
    Hill, E.R., Grantz, A., May, S.D., and Smith, M., 1984, Bathymetric map of the Chukchi Sea: U.S. Geological Survey, Miscellaneous Investigations Series I-1182-D.
    U.S. Geological Survey, 1988, Bathymetric Map of the Bowers Basin and Aleutian Basin east of the U.S.-U.S.S.R. 1867 Convention Line, Bering Sea: Open-File Report 89-548, U.S. Geological Survey, Menlo Park, CA.

    Other_Citation_Details:
    Hall, R.K., Karl, H.A., Carlson, P.R., Cooper, A.K., Gardner, J..V., Hunter, R.E., Marlow, M.S., and Stevenson, A.J., 1989, Bathymetric map of the Aleutian Basin and Bowers Basin east of the U.S.-U.S.S.R. 1867 Convention Line, Bering Sea: U.S. Geological Survey Open-File Report 89-548, 6 pp, 1 map, scale 1:2,000,000.
    Geological Society of America, 1974, Bathymetric Map of the Bering Sea: Geological Society of America, Boulder, CO.

    Other_Citation_Details:
    Pratt, R., and Walton, F., 1974, Bathymetric map of the Bering Sea: The Geological Society of America, Boulder, CO.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Attribute accuracy was tested by manually comparing hard copy plots to the source maps.
  2. How accurate are the geographic locations?
    Horizontal accuracy was tested using Arc/INFO's RMS errors generated when the digitized map is converted from table inches to real world coordinates. RMS errors ranged from 0.002 to 0.004 during map registration. In addition, the joined maps were displayed with Russian and Alaska coastlines with high accuracy. There are several islands in the Aleutian chain that appear to cross the closest bathymetric contour, a problem that may be related to the resolution and accuracy of the coastline coverage as much as the bathymetry coverage.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    All contours for both maps were digitized at a high level of accuracy. After digitizing was completed , a 1:2,000,000 scale coastline (source = digital chart of the world) was added to the coverage to provide a land reference and complete the nearshore polygons.
  5. How consistent are the relationships among the observations, including topology?
    All polygon features are checked for topology using Arc/INFO software. Each polygon begins and ends with a node feature. All nodes are checked for errors so that there are no dangling features. There are no duplicate lines or polygons. All nodes well snap together and close polygons based on a specified tolerance. If the node is not within tolerance it is adjusted manually. The tests for logical consistency are performed in Arc/INFO.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
Use_Constraints:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey and Geological Society of America as the originator of the dataset.
  1. Who distributes the data set? (Distributor 1 of 1)
    Alaska Science Center, Marine and Fresh Water Ecology Branch
    1011 E. Tudor Road
    Anchorage, Alaska
    USA

    907-786-3512 (voice)
    907-786-3636 (FAX)
    Hours_of_Service: 8:00am to 4:00pm Monday through Friday
    Contact_Instructions: None
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS) no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that these data are directly acquired from USGS server, and not indirectly through other sources which may have changed the data in some way. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. The USGS shall not be held liable for improper or incorrect use of the data described and/or contained herein.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 18-Nov-2021
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/AlaskaScienceCtr/berchuk_metadata.faq.html>
Generated by mp version 2.9.50 on Fri Nov 19 13:02:53 2021