U.S. Geological Survey 19970430 vector digital data Anchorage, Alaska U.S. Geological Survey Citation of the source map: 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. https://cmgds.marine.usgs.gov/data/walrus/chukbath.zip Bathymetric contours were generated from soundings collected during geophysical surveys conducted by the USGS from 1969 to 1982, and supplemented by data from other sources. The region covered by the map is the Chukchi Sea from the Bering Strait north to the Arctic Ocean, and Point Barrow, Alaska west to Herald Island, Russia. The map stops just east of Wrangel Island, Russia. Bathymetry is in meters, including 10 meter contour intervals from 10 to 100 meters, and 100 meter contour intervals at depths greater than 100 meters. The bathymetric map was produced to provide a base for displaying further geophysical and biological data. It was not intended to be used for navigation. 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 Chukchi Sea" is titled CHUKBATH_3GEO (chuk=chukchi sea, bath=bathymetry, 3=polygon topology, geo=geographic projection) 1984 map publication date Complete None -176 -153 74.5 65.5 USGS Metadata Identifier USGS:fabbdade-7feb-4e1e-84f5-b73fd8243b6a ISO 19115 Topic Category geoscientificInformation oceans None contours Data Categories for Marine Planning distributions bathymetry and elevation USGS Thesaurus bathymetry contouring computational methods None northwest Alaska northeast Russia Chukchi Sea Arctic Ocean None 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. Not to be used for navigation purposes. Alaska Science Center, Marine and Fresh Water Ecology Branch mailing and physical

Biological Resources Division, U.S. Geological Survey

1011 E. Tudor Road

Anchorage Alaska 99503 USA 907-786-3512 907-786-3636 8:00 am to 4:00pm Monday through Friday None Esri Arc/INFO 7.1 National Ocean Service U.S. Department of Commerce Unknown Map Washington, D.C. Department of Commerce, NOAA, NOS Bathymetric maps available for purchase from National Geophysical Data Center, E/GC3, 325 Broadway, Boulder, Colorado 80303-3228. U.S. Geological Survey 1976 Map U.S. Geological Survey Professional Paper 759-B Washington, D.C. U.S. Government Printing Office 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 1988 Map Open-File Report 89-548 Menlo Park, CA U.S. Geological Survey 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. U.S. Geological Survey 1976 Map Open-File Report 76-821 and 76-823 Washington, D.C. U.S. Geological Survey 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. Geological Society of America 1974 Map Boulder, CO Geological Society of America Pratt, R., and Walton, F., 1974, Bathymetric map of the Bering Sea: The Geological Society of America, Boulder, CO. Attribute accuracy was tested by manually comparing hard copy plots to the source maps. 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. Contours were digitized at 10 meter intervals from 10 meters to 100 meters. Several intermediate contours (e.g. 5, 15, 25, etc.) were not digitized, many were dangling arcs which could not be used to build polygons. From 100 meters to 1,000 meters contours were digitized at 100 meter intervals, same as the resolution on the source map. Beyond 1,000 meters, contours were digitized at 1,000 meter intervals, while the map resolution contained 100 meter intervals. A 1:2,000,00 scale coastline (source = digital chart of the world) was added to the coverage to provide a land reference. 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 for this map ranged from 0.02 to 0.09 which are very poor. Reasons for the high errors may include lack of projection information provided on the source map, errors described in the documentation with the source map, creases in the paper, and/or characteristics of paper media. However, the map accurately overlays plots of the Russian and Alaskan coastlines, so we assume that overall error is minimal (see process description below). U.S. Geological Survey 1984 Miscellaneous Investigations Series Map I-1182-D Washington, D.C. U.S. Geological Survey 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. Map 1984 Publication date USGS_chukbath The map provided the bathymetric contours for the digitized vector data The source map was in Polar Stereographic projection, scale 1:1,000,000 at latitude 72 00 N, no central meridian was provided with the source map, and none could be determined. A tic base from a previous digitizing effort of the same map was used because it provided the best accuracy (history of the existing tic base, and why it is relatively accurate, is not available). The source map was hand digitized and registered into Albers 154 projection to match the tic base. After the map was digitized, 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 70 meters, grain 70 meters, dangle 0.1 meters, and fuzzy 0.1 meters. Note that the tolerances are listed in meters and the coverage is in geographic. THESE TOLERANCES SHOULD BE SPECIFIED IN ANY FUTURE BUILD OR CLEAN TO MAINTAIN THE INTEGRITY OF THE COVERAGE. USGS_chukbath 199609 Alaska Science Center, Marine and Fresh Water Ecology Branch mailing and physical

Biological Resources Division, U.S. Geological Survey

1011 E. Tudor Road

Anchorage Alaska 99503 USA 907-786-3512 907-786-3636 8:00 am to 4:00pm Monday through Friday None Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. 20170214 U.S. Geological Survey Alan O. Allwardt Contractor -- Information Specialist mailing and physical address

2885 Mission Street

Santa Cruz CA 95060 831-460-7551 831-427-4748 aallwardt@usgs.gov Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. 20201019 U.S. Geological Survey VeeAnn A. Cross Marine Geologist Mailing and Physical

384 Woods Hole Road

Woods Hole MA 02543-1598 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov 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. 20211118 U.S. Geological Survey Susan Cochran Geologist Mailing and Physical

2885 Mission Street

Santa Cruz CA 95060 831-460-7545 scochran@usgs.gov Bathymetric contours Vector String 751 Entity point 105 GT-polygon composed of chains 105 Entity point 20 3.53204995917622e-005 3.53204995917622e-005 Decimal Degrees D Clarke 1866 Clarke 1866 6378206.4 294.9786982 No correction 100 meters; 10m and 100m contours are represented Attribute values chukbath_3geo.aat Bathymetric Map of the Chukchi Sea Arc Attribute Table (arcs) USGS; ESRI FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Coordinates defining the features. FNODE# Internal node number for the beginning of an arc (from-node). ESRI Whole numbers that are automatically generated. TNODE# Internal node number for the end of an arc (to-node). ESRI Whole numbers that are automatically generated. LPOLY# Internal node number for the left polygon. ESRI Whole numbers that are automatically generated. RPOLY# Internal node number for the right polygon. ESRI Whole numbers that are automatically generated. LENGTH Length of feature in internal units. ESRI Positive real numbers that are automatically generated. CHUCKBATH# Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. CHUKBATH-ID User-defined feature number. ESRI Sequential unique whole numbers that are automatically generated. DEPTH Depth in meters below sea level for each contour. USGS 20 8000 meters CLASS A categorical variable to define the line type. 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. chukbath_3geo.pat Bathymetric Map of the Chukchi Sea Polygon Attribute Table (polygons) USGS; ESRI FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Coordinates defining the features. AREA Area of feature in internal units squared. ESRI Positive real numbers that are automatically generated. PERIMETER Perimeter of feature in internal units. ESRI Positive real numbers that are automatically generated. CHUCKBATH# Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. CHUCKBATH-ID User-defined feature number. 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. USGS 25 8000 The coverage contains two attributes pertinent for data analysis and display (depth and mid-depth), and one attribute that specifies 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 bathymetric contours, 8 for arcs added to close polygons, and 9 for the coastline. Producer Alaska Science Center, Marine and Fresh Water Ecology Branch Mailing and physical

1011 E. Tudor Road

Anchorage Alaska 99503 USA 907-786-3512 907-786-3636 8:00am to 4:00pm Monday through Friday None 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. ArcInfo Interchange Version 7.1 ArcInfo Interchange file (E00) and Zip (.zip) 0.546 https://cmgds.marine.usgs.gov/data/walrus/chukbath.zip Use internet browse or file manager application (such as Windows Explorer) to access the directory (http://cmgds.marine.usgs.gov/data/walrus/) and download chukbath.zip None, if obtained online. 20211118 U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

2885 Mission Street

Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998