This file is based on the BOEM - Geospatial Services Divisionâs Official Protraction Diagram (OPD) and Leasing Maps (LM). The OPDs and LMs and Supplemental Official Block Diagrams (SOBDs) serve as the legal definition for BOEM offshore boundary coordinates and area descriptions. OPDs are numbered using the United Nations International Map of the World Numbering System, and are generally named for land or hydrographic features contained within the limits of the diagram. The use of OPDs and LMs makes it easier to refer to individual blocks within a region or planning area. Leasing Maps are part of an older system still in use in the Gulf of Mexico. OPDs were built where existing oil and gas leases, at the time, had not yet occurred and where LMs had not yet been established. This data set contains Official Protraction Diagram (OPD) and Leasing Map (LM) outlines in ESRI shape file formats for the BOEM Gulf of Mexico Region. In order to produce a file containing all the OPDs in a region â Official UTM OPDs and State Plane projected LM outlines were re-projected to basic geographic NAD27 unprojected space in order to create a continuous file. Because GIS projection and topology functions can change or generalize coordinates, these GIS files are NOT an OFFICIAL record for the exact OPD or LM boundaries. Only the official projected paper OPD or LM or a digital image (pdf) of them serves as OFFICIAL records. These can be found at the following location: https://www.boem.gov/Official-Protraction-Diagrams.