Gulf of Mexico NAD83 Cadastral Data

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 of Mexico 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 Mexico 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.

Individual Gulf of Mexico Region NAD83 OPDs and OPADs
OPD Name	OPD Files	OPAD Files
Gulf of Mexico Region OPD Index GOM83 OPDlndex.pdf	Gulf of Mexico OPDs PDF File Bundle GOM83-OPDs.zip	Gulf of Mexico OPAD PDF File Bundle GOM83-OPADs.zip
NG14-09 Brownsville	NG14-09-01-Nov-2022.pdf	NG14-09-01-Nov-2022-OPAD.pdf
NG14-06 Port Isabel	NG14-06-01-Nov-2022.pdf	NG14-06-01-Nov-2022-OPAD.pdf
NG14-03 Corpus Christi	NG14-03-01-Nov-2022.pdf	NG14-03-01-Nov-2022-OPAD.pdf
NH14-12 Beeville	NH14-12-01-Nov-2022.pdf	NH14-12-01-Nov-2022-OPAD.pdf
NG15-01 East Breaks	NG15-01-01-Nov-2022.pdf	NG15-01-01-Nov-2022-OPAD.pdf
NG15-02 Garden Banks	NG15-02-01-Nov-2022.pdf	NG15-02-01-Nov-2022-OPAD.pdf
NG15-03 Green Canyon	NG15-03-01-Nov-2022.pdf	NG15-03-01-Nov-2022-OPAD.pdf
NH15-10 Bay City	NH15-10-01-Nov-2022.pdf	NH15-10-01-Nov-2022-OPAD.pdf
NH15-11 Bouma Bank	NH15-11-01-Nov-2022.pdf	NH15-11-01-Nov-2022-OPAD.pdf
NH15-12 Ewing Bank	NH15-12-01-Nov-2022.pdf	NH15-12-01-Nov-2022-OPAD.pdf
NH15-07 Houston	NH15-07-01-Nov-2022.pdf	NH15-07-01-Nov-2022-OPAD.pdf
NH15-08 Port Arthur	NH15-08-01-Nov-2022.pdf	NH15-08-01-Nov-2022-OPAD.pdf
NH15-09 New Orleans	NH15-09-01-Nov-2022.pdf	NH15-09-01-Nov-2022-OPAD.pdf
NH16-10 Mississippi Canyon	NH16-10-01-Nov-2022.pdf	NH16-10-01-Nov-2022-OPAD.pdf
NH16-07 Viosca Knoll	NH16-07-01-Nov-2022.pdf	NH16-07-01-Nov-2022-OPAD.pdf

GIS Files

The various cadastre data is offered as a static file geodatabase . The Gulf of Mexico NAD83 Regional File Geodatabase 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.