1 Identification Information

1.1 Citation Information:

8.1 Originator: United States Geological Survey

8.2 Publication Date: 1976

8.4 Title:

Bathymetric Map of the Chukchi Sea and Arctic Ocean & Bathymetric Map of the Aleutian Trench and Bering Sea

8.7.1 Series Name: Open File Report

8.7.2 Issue Identification: 76-821 and 76-823

8.8.1 Publication Place:

Washington D.C.

8.8.2 Publisher:

U.S. Geological Survey

8.9 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.

1.2 Description

1.2.1 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. In digital format the 2 maps have been connected where they overlap in the Bering Strait.

1.2.2 Purpose:

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

1.2.3 Supplemental Information:

completed coverage stored on ASC workstation GULO in the following directory: /gulo1/ecosys/bathy/final. The coverage is titled BERCHUK_3GEO (ber=bering sea, chuk=chukchi sea, 3=polygon topology, geo=geographic projection.

1.3 Time Period Of Content

1.3.1 Currentness Reference: Publication Date

1.4 Status

1.4.1 Progress: Complete

1.4.2 Maintenance and Update Frequency: None Planned

1.5 Geographic Extent

1.5.2 Bounding Rectangle Coordinates

1.5.2.1 West Bounding Coordinate: 154

1.5.2.2 East Bounding Coordinate: -130

1.5.2.3 North Bounding Coordinate: 76

1.5.2.4 South Bounding Coordinate: 48

1.6 Keywords

1.6.1.1 Theme Keyword Thesaurus: None

1.6.2.1 Place Keyword Thesaurus: None

1.6.3.1 Stratum Keyword Thesaurus: None

1.6.4.1 Temporal Keyword Thesaurus: None

1.10 Point of Contact

10.2 Contact Organization Primary

10.1.2 Contact Organization: Alaska Science Center, Marine and Fresh Water Ecology Branch

10.4 Contact Address

10.4.1 Address Type: Mailing and Physical Address

10.4.2 Address: Biological Resources Division, U.S. Geological Survey

10.4.2 Address: 1011 E. Tudor Road

10.4.3 City: Anchorage

10.4.4 State or Province: Alaska

10.4.5 Postal Code: 99503

10.4.6 Country: USA

10.5 Contact Voice Telephone: (907) 786-3512

10.7 Contact Facsimile Telephone: (907) 786-3636

10.9 Hours of Service: 8:00 a.m. to 4:00 p.m. Monday Through Friday

10.10 Contact Instructions: None

1.14 Native Data Set Environment: UNIX-ARC/INFO

1.15 Cross Reference

8.1 Originator: United States Geological Survey

8.2 Publication Date: 1988

8.4 Title:

Bathymetric Map of the Bowers Basin and Aleutian Basin east of the U.S.-U.S.S.R. 1867 Convention Line, Bering Sea

8.6 Data Presentation Form: Map

8.7.1 Series Name: Open File Report

8.7.2 Issue Identification: 89-548

8.8.1 Publication Place:

U.S. Geological Survey, Menlo Park, California

8.8.2 Publisher:

United States Geological Survey

8.9 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.

8.10 Online Linkage: http://walrus.wr.usgs.gov

8.1 Originator: United States Geological Survey

8.2 Publication Date: 1976

8.4 Title:

Plate 1. Topographic and Bathymetric map of the Northern Bering Sea Region

8.7.1 Series Name: Geological Survey Professional Paper

8.7.2 Issue Identification: 759-B

8.8.1 Publication Place:

Washington D.C.

8.8.2 Publisher:

U. S. Government Printing Office

8.9 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.

8.1 Originator: United States Geological Survey

8.2 Publication Date: 1984

8.4 Title:

Bathymetric map of the Chukchi Sea

8.7.1 Series Name: Miscellaneous Investigations Series

8.7.2 Issue Identification: Map I-1182-D

8.8.2 Publisher:

United States Geological Survey

8.9 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.

2 Data Quality Information

2.1 Attribute Accuracy

2.1.1 Attribute Accuracy Report:

Attribute accuracy was tested by manually comparing hard copy plots to the source maps.

2.2 Logical Consistency Report:

All polygon features were 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.

2.3 Completeness Report:

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.

2.4 Positional Accuracy

2.4.1 Horizontal Positional Accuracy

2.4.1.1 Horizontal Positional Accuracy Report:

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.

2.5.2 Source Information

2.5.2.1 Source Citation:

8.1 Originator: United States Geological Survey

8.2 Publication Date: 1976

8.4 Title:

Bathymetric Map of the Chukchi Sea and Arctic Ocean & Bathymetric Map of the Aleutian Trench and Bering Sea

8.7.1 Series Name: Open File Report

8.7.2 Issue Identification: 76-821 and 76-823

8.8.1 Publication Place:

Washington D.C.

8.8.2 Publisher:

U.S. Geological Survey

8.9 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.

2.5.2.2 Source Scale Denominator: 2500000

2.5.2.3 Type Of Source Media: Paper

2.5.2.4 Source Time Period Of Content:

2.5.2.4.1 Source Currentness Reference: Publication Date

2.5.3 Process Step

2.5.3.1 Process Description:

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.

2.5.3.3 Process Date: 199609

2.5.3.6 Process Contact:

10.2 Contact Organization Primary

10.1.2 Contact Organization: Alaska Science Center, Marine and Fresh Water Ecology Branch

10.4 Contact Address

10.4.1 Address Type: Mailing and Physical Address

10.4.2 Address: Biological Resources Division, U.S. Geological Survey

10.4.2 Address: 1011 E. Tudor Road

10.4.3 City: Anchorage

10.4.4 State or Province: Alaska

10.4.5 Postal Code: 99503

10.4.6 Country: USA

10.5 Contact Voice Telephone: (907) 786-3512

10.7 Contact Facsimile Telephone: (907) 786-3636

10.9 Hours of Service: 8:00 a.m. to 4:00 p.m. Monday Through Friday

10.10 Contact Instructions: None

3 Spatial Data Organization Information

3.1 Indirect Spatial Reference:

bathymetric contours

3.2 Direct Spatial Reference Method: Vector

3.3 Point and Vector Object Information

3.3.1.1 SDTS Point and Vector Object Type: arcs

3.3.1.2 Point and Vector Object Count: 2955

3.3.1.1 SDTS Point and Vector Object Type: polygons

3.3.1.2 Point and Vector Object Count: 376

3.3.1.1 SDTS Point and Vector Object Type: label points

3.3.1.2 Point and Vector Object Count: 376

4 Spatial Reference Information

4.1 Horizontal Coordinate System Definition

4.1.2 Planar

4.1.2.1.1 Map Projection Name: latitude/longitude geographic

4.1.4.1 Horizontal Datum Name: North American Datum of 1927

4.1.4.2 Ellipsoid Name: Clarke 1866

4.2.2.1 Depth Datum Name: No Correction

4.2.2.2 Depth Resolution: 400

4.2.2.2 Depth Resolution: 10

4.2.2.2 Depth Resolution: 50

4.2.2.3 Depth Distance Units: meters

4.2.2.4 Depth Encoding Method: Attribute Values

5 Entity and Attribute Information

5.1 Detailed Description

5.1.2 Attribute

5.1.2.1 Attribute Label: depth

5.1.2.2 Attribute Definition:

depth in meters below sea level for each contour

5.1.2.4.2 Range Domain 20

5.1.2.4.2.1 Range Domain Minimum: 20

5.1.2.4.2.2 Range Domain Maximum: 8000

5.1.2.5 Attribute Units Of Measurement: meters

5.1.2 Attribute

5.1.2.1 Attribute Label: mid-depth

5.1.2.2 Attribute Definition:

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.

5.1.2.4.2 Range Domain 25

5.1.2.4.2.1 Range Domain Minimum: 25

5.1.2.4.2.2 Range Domain Maximum: 8000

5.1.2.5 Attribute Units Of Measurement: meters

5.1.2 Attribute

5.1.2.1 Attribute Label: class

5.1.2.2 Attribute Definition:

a categorical variable to define the line type. 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.

5.2 Overview Description

5.2.1 Entity and Attribute Overview:

The coverage contains two attributes pertinant 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.

6 Distribution Information

6.1 Distributor

10.2 Contact Organization Primary

10.1.2 Contact Organization: Alaska Science Center, Marine and Fresh Water Ecology Branch

10.4 Contact Address

10.4.1 Address Type: Mailing and Physical Address

10.4.2 Address: Biological Resources Division, U.S. Geological Survey

10.4.2 Address: 1011 E. Tudor Road

10.4.3 City: Anchorage

10.4.4 State or Province: Alaska

10.4.5 Postal Code: 99503

10.4.6 Country: USA

10.5 Contact Voice Telephone: (907) 786-3512

10.7 Contact Facsimile Telephone: (907) 786-3636

10.9 Hours of Service: 8:00 a.m. to 4:00 p.m. Monday Through Friday

10.10 Contact Instructions: None

6.3 Distribution Liability:

Although these data have been processed successfully on a computer system at the Alaska Science Center, Biological Resources Division, US Geological Survey, 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 an Alaska Science Center 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 Alaska Science Center shall not be held liable for improper or incorrect use of the data described and/or contained herein.

6.4 Standard Order Process

6.4.1 Non-Digital Form: maps. Open file reports 76-821 and 76-823

6.4.3 Fees: contact USGS for fee information

6.4.4 Ordering Instructions: USGS Information Services, Box 25046, MS 507, Denver, CO 80225 USA [303-202-4210; or USGS National Mapping Division, Map Sales, 4230 University Drive, Anchorage, AK 99508 USA [907-786-7011]

6.4 Standard Order Process

6.4.2 Digital Form

6.4.2.1.1 Format Name: ARC/INFO

6.4.2.1.2 Format Version Number: Version 7.1

6.4.2.1.6 File Decompression Technique: Arc Export (full compression)

6.4.2.1.7 Transfer Size: 9795807

6.4.2.2 Digital Transfer Option

6.4.2.2.1.2 Access Instructions: FTP:ftp.asc.nbs.gov, access ftp site as anonymous, change directory to OUTGOING/BATHY, transfer under ASCII mode (type ascii), get BERCHUK_3GEO.E00

6.4.3 Fees: None

7 Metadata Reference Information

7.1 Metadata Date: 19961002

7.4 Metadata Contact:

10.2 Contact Organization Primary

10.1.2 Contact Organization: Alaska Science Center, Marine and Fresh Water Ecology Branch

10.4 Contact Address

10.4.1 Address Type: Mailing and Physical Address

10.4.2 Address: Biological Resources Division, U.S. Geological Survey

10.4.2 Address: 1011 E. Tudor Road

10.4.3 City: Anchorage

10.4.4 State or Province: Alaska

10.4.5 Postal Code: 99503

10.4.6 Country: USA

10.5 Contact Voice Telephone: (907) 786-3512

10.7 Contact Facsimile Telephone: (907) 786-3636

10.9 Hours of Service: 8:00 a.m. to 4:00 p.m. Monday Through Friday

10.10 Contact Instructions: None

7.5 Metadata Standard Name: FGDC Content Standards For Digital Geospatial Metadata

7.6 Metadata Standard Version: June 8, 1994

7.7 Metadata Time Convention: Local Time

Please send comments or questions about the content of this page to Chad Jay or Tony Fischbach

Please send comments or questions about this web page to: mwhalen@usgs.gov