This data set contains Official Protraction Diagram (OPD) outlines in ESRI shapefile format. At lower latitudes (0-48 degrees) OPDs are 1 degree in latitude by 2 degrees in longitude. At higher latitudes (48-75 degrees) OPDs are 3 degrees wide. OPDs are further subdivided into blocks that are 4800 x 4800 meters on a UTM grid (but this file does not include those blocks - only the OPD outline). Where the OPD hits the UTM zone boundary, that zone boundary will be a geodesic line - which will appear slightly curved on the UTM grid. OPDs are numbered using the United Nations International Map of the World Numbering System, and are generally named for land or hydrographic features contained within the limits of the diagram. Further information on the historic development of OPD's can be found in OCS Report MMS 99-0006: Boundary Development on the Outer Continental Shelf: http://www.boem.gov/BOEM-Newsroom/Library/Publications/1999/99-0006-pdf.aspx Because GIS projection and topology functions can change or generalize coordinates, these GIS files are considered to be approximate and are NOT an OFFICIAL record for the exact OPD coordinates or areas. The Official Protraction Diagrams (OPDs) and Supplemental Official OCS Block Diagrams (SOBDs), available on the web in pdf format, serve as the legal definition for BOEM offshore boundary coordinates and area descriptions.
These block polygons and other cadastre information the BOEM produces are generated in accordance with 30 Code of Federal Regulations (CFR) 256.8 to support Federal land ownership and mineral resource management.
The BOEM is making its existing cadastre data available at http://www.boem.gov/Oil-and-Gas-Energy-Program/Mapping-and-Data/Index.aspx. These data include Official Protraction Diagrams (OPDs), and Supplemental Official OCS Block Diagrams (SOBDs) in pdf format, and digital spatial data in ArcGIS shapefile format.
publication date
The data was developed within the U.S. Government; no proprietary rights may be attached to them nor may they be sold to the U.S. Government as part of any procurement of digital data products or services.
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The file is believed to be free of topologic errors.
The entire Alaska Region consists of 285 NAD 83 Official Protraction Diagrams (OPDs), yet not all have been published in the federal register. A total of 69 OPDs remain to be published. The browse graphic distinguishes the difference between the published OPDs and the unpublished OPDs. Another way to tell if an OPD is published or unpublished is by looking at the PROT_APRV_ field in the attribute table. If the PROT_APRV_ field is blank, then the OPD is considered unpublished. The completion date of the entire Alaska Region OPDs is unknown at this time.
Coordinates values have been computed to .00000001 of a degree, but this shapefile is considered to be approximate. Where differences occur between the shapefile and the OPD and SOBD diagrams, the diagrams take precedence.
Coordinates and attributes for OPD polygons.
In house programs were used to protract offshore blocks OPD by OPD, on a UTM grid for the offshore areas. The resulting points were then stored in the TIMS database. Other in-house programs were used to create an ArcInfo Coverage from the data stored in the TIMS database. That coverage was converted into a shapefile using ArcGIS.
381 Elden St.
Mail Stop HM3120
Dataset copied.
Internal feature number.
ESRI
Feature geometry.
ESRI
Area is computed by ESRI in coverage units (square degrees) - NOT the official BOEM TIMS acreage
ESRI
Perimeter is computed by ESRI in coverage units (degrees) - NOT the official BOEM TIMS measurement
ESRI
Region Code is the identifier used to identify the BOEM Outer Continental Shelf (OCS) Region.
Bureau of Ocean Energy Management
Protraction Number is the identifier of an Official Protraction Diagram
Bureau of Ocean Energy Management
Protraction Approval Date is the day, month and year the Official Protraction Diagram is signed by the Federal Government and approved for distribution.
Bureau of Ocean Energy Management
Official Protraction Diagram Name is the name as it appears on the actual document.
Bureau of Ocean Energy Management
OPD Map Projection Zone Code are an indicator of the map projection and UTM zone for map computation and plotting purposes.
Bureau of Ocean Energy Management
Atttributes to describe the OPDs, primarily the Protraction number and approval date.
Bureau of Ocean Energy Management
381 Elden St.
Mail Stop HM3120
As is. No responsibility is assumed for the correctness of this data.
381 Elden St
Mail Stop HM3120