Coastal Bathymetry of the Bering, Chukchi and Beaufort Seas

Metadata:

Identification_Information
Data_Quality_Information
Spatial_Data_Organization_Information
Spatial_Reference_Information
Entity_and_Attribute_Information
Distribution_Information
Metadata_Reference_Information

Identification_Information:

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:: 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.

Logical_Consistency_Report:

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.

Completeness_Report:

Contours were digitized from NOS bathymetric maps (90 percent) or generated from NOS bathymetric sounding point data (10 percent) 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 1:250000 Alaska Department of Natural Resources coastline was added to the coverage to provide a land reference.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:: Horizontal positional accuracy was tested using ARC/INFO's RMS errors generated when the the digitzed map is converted from table inches to real world coordinates. RMS errors averaged 150m for the approximately 100 maps digitized.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: United States Geological Survey
Publication_Date: 19740000
Title: Bathymetric Map of the Bering Shelf

Type_of_Source_Media: Map

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 19740000

Source_Currentness_Reference: Publication date

Source_Citation_Abbreviation:

The Geological Society of America. 1974. Bathymetric Map of the bering Shelf. The Geological Society of America, Boulder, CO.

Source_Contribution: Map Compiled by Richard Pratt and Fred Walton, NOS

Source_Information:

Source_Citation:

Citation_Information:

Originator: United States Geological Survey
Publication_Date: 19760000
Title:: Bathymetric Map of the Chukchi Sea and Arctic Ocean & Bathymetric Map of the Aleutian Trench and Bering Sea

Type_of_Source_Media: Open file report

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 19740000

Source_Currentness_Reference: Publication date

Source_Citation_Abbreviation:

United States Geological Survey, 1976. Bathymetric Map of the Chuckchi Sea and Arctic Ocean and Bathymetric Maps of the Aleutian Trench and bering Sea. Open File Reports 76-821 and 76-823. US Geological Survey, Washington D.C.

Source_Contribution: Schumacher, G. M.

Source_Information:

Source_Citation:

Citation_Information:

Originator: United States Geological Survey
Publication_Date: 19760000
Title:: Opographic and Bathymetric map of the Northern Bering Sea Region

Type_of_Source_Media: Geological Survey Professional Paper

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 19740000

Source_Currentness_Reference: Publication date

Source_Citation_Abbreviation:

U.S. Geological Survey. 1976. Plate 1 Topographic and Bathymetric Map of the Northern Bering Sea region. USGS Professional Paper 759-B. US Government Printing Office, Washington DC.

Source_Contribution: D.M. Hopkins, C.H.Nelson, R.B. perry, T.R. Ralph

Source_Information:

Source_Citation:

Citation_Information:

Originator: United States Geological Survey
Publication_Date: 19840000
Title: Bathymetric map of the Chukchi Sea

Type_of_Source_Media: Miscellaneous Investigations Series

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 19740000

Source_Currentness_Reference: Publication date

Source_Citation_Abbreviation:

USGS. 1984. Bathymetric Map of the Chukchi Sea. Misc. Investigations Series Map I-1182-D. USGS. Washigton D.C.

Source_Contribution: E.R. Hill, A. Grantz, S.D. May, M. Smith

Process_Step:

Process_Description:: Approximately 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.
Process_Date: 19970000

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: Ring composed of arcs
Point_and_Vector_Object_Count: 14861
SDTS_Point_and_Vector_Object_Type: G-polygon
Point_and_Vector_Object_Count: 10345
SDTS_Point_and_Vector_Object_Type: Label point
Point_and_Vector_Object_Count: 10345

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: Albers Conical Equal Area

Albers_Conical_Equal_Area:

Standard_Parallel: 55
Standard_Parallel: 65
Longitude_of_Central_Meridian: -154
Latitude_of_Projection_Origin: 50
False_Easting: 0
False_Northing: 0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: Coordinate pair

Coordinate_Representation:

Abscissa_Resolution: Unknown Ordinate Resolution: Unknown

Planar_Distance_Units: Meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1927
Ellipsoid_Name: Clarke 1866
Semi-major_Axis: 6378206.4
Denominator_of_Flattening_Ratio: 294.98

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: ELEVATION (polygon attribute)
Entity_Type_Definition:: Midpoint of bounding arcs, eg the elevation between -10 and -20m 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.
Entity_Type_Definition_Source: U.S. Department of Commerce

Entity_Type:

Entity_Type_Label: Elevation (vector attribute)
Entity_Type_Definition:: Depth of bathymetric contour, 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.
Entity_Type_Definition_Source: U.S. Department of Commerce

Entity_Type:

Entity_Type_Label: Methods
Entity_Type_Definition:: An arc attribute describing the method used to develop contours. Contours digitized from the NOS maps are coded "DIGITIZE", and contours that were generated from the NOS survey point data are coded "GENERATE".
Entity_Type_Definition_Source: Resource Data Inc.

Overview_Description:

Entity_and_Attribute_Overview: Ocean depths
Entity_and_Attribute_Detail_Citation: None

Distribution_Information:

Metadata_Reference_Information:

Metadata_Date: 19971001

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:: USGS Biological Resources Div., Alaska Biological Science Center
Contact_Person: David C. Douglas

Contact_Address:

Address_Type: mailing address
Address: 1011 East Tudor Road
City: Anchorage
State_or_Province: Alaska
Postal_Code: 99503
Country: USA

Contact_Voice_Telephone: 907-786-3512

Contact_Electronic_Mail_Address: david_douglas@usgs.gov

Contact_Instructions:

The USGS/BRD Alaska Biological Science Center will be making an effort to keep the information provided in these metadata records current. Please send corrections, additions and suggestions for improvement to David Douglas at the above address.

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: June 8, 1994

Generated by mp on Tue Oct 7 16:44:18 1997