A standard OPD is 1 degree in latitude by 2 degrees in longitude (at lower latitudes: 0 - 48 degrees). At higher latitudes (48 - 75 degrees) such as Alaska and northern Washington, OPDs are 3 degrees wide. OPD limits usually approximate the standard 1:250,000 scale U.S. Geological Survey topographic map series. The OPDs are numbered using the United Nations International Map of the World Numbering System. OPD names usually coincide with standard topographic sheet names when diagrams include land areas. OPD sheet names relate to land features, or to hydrographic features contained within the limits of the diagram. Shoreline planimetric detail is shown when it falls within the limits of a diagram. Older OPDs were prepared on mylar with manual cartographic methods and then scanned into Adobe .pdf files. Newer OPDs were prepared electronically and converted to Adobe .pdf files.

The various boundaries are also offered as ESRI ArcGIS shapefiles. Shapefiles can be viewed with the free Arc Explorer viewer, ArcGIS, or a variety of other GIS systems. The shape files have been zipped using WinZip.

Note: The precise coordinates of a GIS file can be altered slightly by various GIS functions. For that reason, these GIS files are not an Official Record for BOEMRE offshore boundaries. Only the coordinates shown on Official OPDs, CBDs, and SOBDs constitute an Official Record for offshore coordinate values.

Note: OPDs have not yet been published for all Alaska offshore areas and only the current versions of published OPDs are available from this site. Please contact the Alaska Region if you are looking for NAD 27, or older superseded NAD 83 versions.

All coordinates are in NAD 83. Alaska Region leases and cadastre data from before 1994 were mapped using the North American Datum of 1927 (NAD 27). These new NAD 83 files do not represent a conversion, but rather a complete re-grid. For further details, see Project Plan for Implementing NAD 83 in the Bureau of Ocean Energy Management, Regulation and Enforcement:

• Part I: Responsibilities and Timeframes

• Part II: Technical Aspects of Implementation

• Summary Status Report

The files below may also be ordered on CD. Contact the Mapping and Boundary Branch.