The Mapping & Boundary Branch performs mathematical offshore boundary location computations and prepares Official Protraction Diagrams (OPDs) and Leasing Maps (LMs), 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.
For clarification of Acronyms, see Codes and Abbreviations for Map/OPD/Area. The analytical procedures employed and the computer programs utilized to perform various offshore boundary geometric computations are described in OCS Report MMS 99-0006.
- Gulf of Mexico Geographic Information System (GIS) Mapping Data
Geographic mapping data available for free downloading includes cadastral, regulatory, and resource features. Some of the numerous files available include lease, block, and protraction polygons, fairways, pipelines and platforms. Three formats are available for download: ArcInfo, ASCII, and DXF.
- Gulf of Mexico Lease Information
Periodically, the Bureau of Ocean Energy Management holds Oil and Gas Lease Sales in the Gulf of Mexico (GOM). Recent sale maps with active leases can be found by viewing the individual sale information from the Lease Sale page.
- General Purpose Maps
- OCS Plans Map for CZM - allows the user to view and query OCS Coastal Zone Management (CZM) Blocks in the Gulf of Mexico
- ROW Pipeline Map for CZM - allows the user to view and query ROW Pipeline Coastal Zone Management (CZM) Blocks
- High-Resolution Geophysical Survey Application - allows the user to view and query High Resolution Geophysical Surveys that were completed in the Gulf of Mexico and submitted to BOEM as Geohazard/Archaeology Reports.
- 2002-2007 Planning Area Legal Descriptions and Statistics
PLAR0207f.PDF (06/20/2002) | PAstats.PDF (09/18/2004)
- GOM Active Leases/Infrastructure
Visual 1 .pdf | Visual 1 eps version (05/05/2021)
Visual 1 Searchable ARCGIS Online Interactive Map (current)
This map displays active leases, oil and gas structures, pipelines, area boundaries, lease term lines, oil refineries, supply bases, crude oil terminals, and water depth in meters.
- Western and Central GOM Topographic Features Stipulation Map Package
These maps indicate the areas affected by the Topographic features Stipulation.
For additional information regarding Biological Stipulations questions may be directed to Mark Belter at (504) 736-1739.
Within the Gulf of Mexico, there are two types of maps that depict blocks that could be leased. An older format, known as the Leasing Map, was based on Texas or Louisiana State Plane mapping projections. Leasing Maps were created as oil/gas leasing expanded offshore of Texas and Louisiana.
Eventually the Leasing Maps were projected so far offshore that negative coordinates were required to support the projection. This has created a wide variety of Leasing Maps in projection, shape and overall size, but the blocks remained consistent, and are never larger than the 5760 acres. Because the Leasing Maps reflect so many active leases, they are still being maintained. However, in areas further offshore where Leasing Maps have never been generated, the Official Protraction Diagram (OPD) are used.
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.
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. 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 Gulf of Mexico Region OPD and SOBD may be viewed and downloaded from the list below. OPDs are offered in Adobe (.pdf) format. OPDs completed after 1996 are also available in Arc/Info Graphics File (.gra) format. SOBDs are available as Adobe (.pdf) files that have been compressed with PKZIP. Free decompression utilities may be downloaded here.
The various boundaries are also offered as GIS files in both Arc/Info export (.e00) format, and as Arc View shapefiles. Shapefiles can also be viewed with the free ArcGIS Explorer viewer. The shape files have been zipped with Winzip. Some .e00 export files have been compressed with the UNIX "compress" command. (If they are compressed they will have a .Z extension.) Use the UNIX "uncompress" utility or the free gzip.exe DOS utility.
OPDs can also be purchased by paper copies as maps or in digital formats from the Public Information Office at 1-800-200-GULF.
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 offshore boundaries. Only the coordinates shown on Official OPDs, CBDs, and SOBDs constitute an Official Record for offshore coordinate values.
Note: All coordinates for the Gulf of Mexico Region leases and cadastre data are done on the North American Datum of 1927 (NAD 27).
- High-Resolution Geophysical Survey Application
- Marine Managed Areas: Best Practices for Boundary Making (Marine Boundaries, Georegulations, Marine Jurisdictions)
- Mapping and Cadastral Data (National Maps and Special Purpose Maps)
- Multipurpose Marine Cadastre Viewer