Geographic Information System (GIS) Data and Maps
The Geospatial Services Division performs mathematical offshore boundary location computations and prepares Official Protraction Diagrams (OPDs) and Official Protraction Aliquot Diagrams (OPADs) depicting OCS Block and Aliquot information, the Submerged Lands Act Boundary, Limit of "8(g)/8(p) Zone", Marine Protected Areas and Maritime Boundaries.
NOTE: Gulf Region OPDs that show the Submerged Lands Act and Section 8(g)/8(p) Zone boundaries do not reflect recent shoreline changes. These boundaries were permanently immobilized (“fixed”) by actions of the Supreme Court for Louisiana (1981), Mississippi (1990), Alabama (1993), and Texas (1998). Accordingly, the shoreline associated with these boundaries as shown on the OPDs has not been updated. At this time, BOEM has completed the Gulf of America NAD83 Cadastre for the extent of the Renewable Energy Call Area.
OPD and OPAD Images
A standard OPD/OPAD 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/OPADs are 3 degrees wide. OPD/OPAD limits usually approximate the standard 1:250,000 scale U.S. Geological Survey topographic map series. The OPDs/OPADs are numbered using the United Nations International Map of the World Numbering System. OPD/OPAD names usually coincide with standard topographic sheet names when diagrams include land areas. OPD/OPAD sheet names relate to either 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.
Listed in the table below are OPDs and OPADs available in PDF format.
NOTE: SOBDs are not currently available for download.
Scroll down the page to access individual OPDs and OPADs available in PDF format.
Offshore Marine Cadastre (OMC) Navigator
The Offshore Marine Cadastre (OMC) Navigator is a national viewer showing Protractions, Blocks, Aliquots, and Boundaries covering the Outer Continental Shelf (OCS). These are units of area measurement that officially describe the OCS and demarcate areas that could be leased for energy in accordance with 30 CFR 550.400, 30 CFR 585.205, and 30 CFR 581.15. The main purpose of the viewer is to provide PDF links to BOEM’s Official Mapping Products known as Official Protraction Diagram Index Maps, Official Protraction Diagrams (OPDs), Official Protraction Aliquots Diagrams (OPADs), and Supplemental Official Block Diagrams (SOBDs).
GIS Files
The various cadastre data is offered as a static file geodatabase . The BOEM Offshore Marine Cadastre Data Collection can be viewed using ArcGIS or a variety of other GIS systems.
NOTE: The precise coordinates of a GIS file can be altered slightly by various GIS functions. Consequently, these GIS files are not an Official Record for BOEM offshore boundaries. Only the coordinates shown on Official OPDs constitute an Official Record for offshore coordinate values.