Geographic Information System (GIS) Data and Maps

The MMS Mapping & Boundary Branch performs mathematical offshore boundary location computations and prepares Official Protraction Diagrams (OPDs), and Supplemental Official OCS Block Diagrams (SOBDs) depicting OCS Block information, the Submerged Lands Act Boundary (aka - State Seaward Boundary), Limit of "8(g) Zone", the Continental Shelf Boundary (CSB) which marks the limit of U.S. jurisdiction for offshore mineral development, and corresponding area measurements. The analytical procedures employed and the computer programs utilized to perform various offshore boundary geometric computations are described in OCS Report MMS 99-0006.

OPD Images

SOBD Images

A Supplemental Official OCS Block Diagram (SOBD) is prepared for each block intersected by an offshore boundary (Submerged Lands Act Boundary, Limit of "8(g) Zone", National Marine Sanctuaries, etc.). Note that not all OPDs contain such boundaries, therefore not all OPDs have SOBDs associated with them. All the SOBDs for a given OPD are zipped into a single file for downloading. The zip files will contain the most recent version, but older historic versions may also be included for reference. For the purpose of future Lease Sales always be sure to use the most recent version.

Image File Formats

The most current approved revision for each Pacific Region OPD and SOBD may be viewed and downloaded from the list below. OPDs are offered in both Arc/Info Graphics File (.gra) format, and Adobe (.pdf) format. SOBDs are available as Adobe (.pdf) files that have been compressed with PKZIP. Adobe (.pdf) files may be viewed with the free Adobe Acrobat reader.

GIS Files

The various boundaries are offered as GIS files in both Arc/Info export (.e00) format and as Arc View shapefiles. Shapefiles can also be viewed with the free Arc Explorer viewer. The shape files have been zipped with Pkzip. The .e00 export files have been compressed with the UNIX "compress" command. (If they are compressed they will have a .Z extension.) If the file transfer process has changed the upper case Z to lower case z you might need to change it back to upper case Z before the UNIX uncompress utility will recognize the file.

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 MMS offshore boundaries. Only the coordinates shown on Official OPDs and SOBDs constitute an Official Record for offshore coordinate values.

All coordinates are in NAD 83. Pacific Region leases and cadastre data from before 1997 were done on the North American Datum of 1927 (NAD 27). These new NAD 83 files do not represent a conversion, but rather a complete regrid. For further details see: Project Plan for Implementing NAD 83 in the Minerals Management Service Part I: Responsibilities and Timeframes, Part II: Technical Aspects of Implementation, and Summary Status Report.

Additional Pacific Data Sources:

	Pacific OCS Lease Information
	Pacific Boundaries and Maps