Coastal Bathymetry of the Bering, Chuckhi, and Beaufort Seas

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Frequently anticipated questions:


What does this data set describe?

Title: Coastal Bathymetry of the Bering, Chuckhi, and Beaufort Seas
Abstract:
Bathymetric contours were generated from soundings collected by National Ocean Service vessels from ~1900 to ~1971. The 1:250,000 maps are available for U.S. coastal waters. Bathymetric contours are in meters, with 10 meter intervals out to 200 m, supplemented by 2 m contours. Beyond 200 m, contours are at 50 m intervals to maximum depth. The GIS database derived from these maps includes the Bering, Chukchi, and Beaufort Seas in western and northern Alaska (~100 maps).
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 "Bathymetry of the Bering Strait: Chukotka to Diomede Island" is titled NOSBATH_3GEO (nos=National Ocean Service, bath=bathymetry, 3=polygon topology, geo=geographic projection)
  1. How might this data set be cited?
    U.S. Geological Survey, 19970430, Coastal Bathymetry of the Bering, Chuckhi, and Beaufort Seas: U.S. Geological Survey, Anchorage, Alaska.

    Online Links:

    Other_Citation_Details:
    Data source is the National Ocean Service (NOS), U.S. Department of Commerce. Maps available for purchase from National Geophysical Data Center, E/GC3, 325 Broadway, Boulder, Colorado 80303-3228.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -178
    East_Bounding_Coordinate: -138
    North_Bounding_Coordinate: 74
    South_Bounding_Coordinate: 53
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date:
    Ending_Date: 1971
    Currentness_Reference:
    map publication dates
  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 (15049)
      • Entity point (10345)
      • GT-polygon composed of chains (10344)
      • Entity point (4)
    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 0.002. Longitudes are given to the nearest 0.002. 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: Mean Lower Low Water
      Depth_Resolution: 10
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    nosbath_3geo.aat
    Coastal Bathymetry of the Bering, Chuckhi, and Beaufort Seas 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.
    NOSBATH#
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    NOSBATH-ID
    User-defined feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    METHODS
    An arc attribute describing the method used to develop contours. (Source: USGS)
    ValueDefinition
    DIGITIZECountours were digitzed from NOS maps
    GENERATECountours were generated from NOS survey point data
    ELEVATION
    Depth of bathymetric contour lines, in negative meters. Used to calculate the polygon mid-depth elevation attribute. Arcs used to define the map boundary, holiday areas, and to clip dangling contours to the next shallowest contour are coded 999. (Source: USGS)Frequency of measurement: Irregular
    Range of values
    Minimum:-10
    Maximum:-200
    Units:meters
    Resolution:10
    nosbath_3geo.pat
    Coastal Bathymetry of the Bering, Chuckhi, and Beaufort Seas 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.
    NOSBATH#
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    NOSBATH-ID
    User-defined feature number. (Source: ESRI) Sequential unique whole numbers that were automatically generated.
    ELEVATION
    Polygon attribute calculated as the mid-point between bounding arcs, eg the elevation between -10 m and -20 m isobaths equals -15 m. Where a bathymetric contour was an "island" and there was no depth information inside the island, the elevation was coded as the bounding contour's depth. Elevations range from -5 to -195 m. Enclosed polygons deeper than 200 m are coded -999. "Holiday areas" with no bathymetric data are coded +999. enclosed polygons outside the map area are coded +998. All land polygons are labeled +5. (Source: USGS)Frequency of measurement: Irregular
    Range of values
    Minimum:-5
    Maximum:-195
    Units:meters
    Resolution:10

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 Bathymetric Map series was developed to provide detailed contours of underwater features. The maps serve as a basic tool for performing scientific, engineering, marine geophysical, and marine environmental studies. The maps were not intended to be used for navigation.

How was the data set created?

  1. From what previous works were the data drawn?
    NOS_bath (source 1 of 1)
    National Ocean Service, Department of Commerce, various, Coastal Shelf Bathymetry of the Bering, Chukchi, and Beaufort Seas: Bathymetric Maps, Department of Commerce, NOAA, NOS, Washington, D.C..

    Other_Citation_Details:
    Maps available for purchase from National Geophysical Data Center, E/GC3, 325 Broadway, Boulder, Colorado 80303-3228.
    Type_of_Source_Media: Maps
    Source_Contribution:
    The maps provided the bathymetric data for generating bathmyetric contours.
  2. How were the data generated, processed, and modified?
    Date: 1997 (process 1 of 2)
    ~100 maps from the NOS Bathymetric Map series were selected to be digitized. Ocean depth point data from National Ocean Service cruises (a subset of the data used to develop the bathymetric map series) was used to generate contours where the map contours were extremely difficult to digitize. The generated contours were usually similar to the map contours, and where large discrepencies occurred the lines were digitized from the maps and the generated contours removed. Contours were generated in north Bristol Bay, small areas on the northwest side of the Alaska Peninsula, around the eastern Aleutian Islands and St. Paul Island, and a large area from Seward Peninsula to St. Lawrence Island. All other areas were digitized from the NOS maps. Areas where NOS had no bathymetric data (defined by NOS as holiday areas) were blocked and defined as areas with no data, no attempt was made to generate contours in these areas. Small holiday areas occurred along the coast of the Aleutian Islands and Alaska Peninsula, west side of Nushagak Peninsula, north of Hagemeister Island, sourth side of St. George Island, north side of Nunavak Island, west and north sides of Seward Peninsula and a small pocket in the Beaufort Sea north of Prudhoe Bay. Larger holiday areas occur at the mouth of the Yukon and Kuskokwim Rivers and around the coast of St. Lawrence Island. Additionally, no map is available for the east end of Kotzebue Sound. Person who carried out this activity:
    Resource Data, Inc., Anchorage, Alaska

    Data sources used in this process:
    • NOS_bath
    Date: 14-Feb-2017 (process 2 of 2)
    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
  3. What similar or related data should the user be aware of?
    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., H.A. Karl, P.R. Carlson, A.K. Cooper, J.V. Gardner, R.E. Hunter, M.S. Marlow, and A.J. Stevenson. 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.
    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., A. Grantz, S. D. May, and M. Smith. 1984. Bathymetric map of the Chukchi Sea. U.S. Geological Survey, Misc. Inves. Series I-1182-D.
    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., C. H. Nelson, R. B. Perry, and T. R. Alpha. 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. 7pp. 3 plates.
    U.S. Geological Survey, 1976, Bathymetric Map of the Chukchi Sea and Arctic Ocean & bathymetric Map of the Aleutian Trench and Bering Sea: 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. Schumacher, G. M. 1976. Bathymetric map of the Aleutian Trench and Bering Sea. USGS Open File Report 76-821.
    Geological Society of America, 1974, Bathymetric Map of the Bering Sea: Geological Society of America, Boulder, CO.

    Other_Citation_Details:
    Pratt, R. and F. Walton. 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. Accuracy of the source maps is related to the contouring algorithm used to derive the contours and changes in bathymetry since the data were collected. The NOS point data near the Aleutian Islands was not well registered with the coastline. Depths up to 30 m crossed the digitized coastline by up to 200 m and were clipped from the final coverage. It is unknown which data were incorrect (digitized coastline or point locations).
  2. How accurate are the geographic locations?
    Horizontal positional 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 averaged 150 m for the ~100 maps digitized.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Contours were digitized from NOS bathymetric maps (~90%) or generated from NOS bathymetric sounding point data (~10%) where digitizing was difficult and high density point data were available. Contours are at 10 m intervals out to 200 m. Intermediate contours were not included, because many were dangling arcs which could not be used to build polygons. Contours beyond 200 m are available on the source maps, but were not included in the GIS database. The source maps included "holiday areas" where NOS collected no sounding data, and no bathymetric contours or points are available, these areas are defined in the coverage. A 1:250,000 Alaska Department of Natural Resources coastline was added to the coverage to provide a land reference.
  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 will snap together and close polygons based on a specified tolerance. If the node is not within the 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 as the originator of the dataset. Data are not to be used for navigation.
  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 US 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: 14-Feb-2017
Metadata author:
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
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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