This data set contains Official Protraction Diagram (OPD) outlines in ESRI shapefile format. Atlantic Region OPDs are approximately 2 degrees wide by one degree high. OPDs are further subdivided into blocks that are 4800 x 4800 meters on a UTM plane (but this file does not include those blocks - only the OPD outline). Where the OPD hits the UTM zone boundary, that zone boundary will be a geodesic line - which will appear slightly curved on the UTM plane. 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. These OPD outlines were clipped along the Submerged Lands Act Boundary (3 mile line), Continental Shelf Boundary (international boundaries), and the dividing line between the Gulf and Atlantic Regions. Further information on the historic development of OPD's can be found in OCS Report MMS 99-0006: Boundary Development on the Outer Continental Shelf: https://www.boem.gov/BOEM-Newsroom/Library/Publications/1999/99-0006-pdf.aspx Because GIS projection and topology functions can change or generalize coordinates, these GIS files are considered to be approximate and are NOT an OFFICIAL record for the exact OPD coordinates or areas. The Official Protraction Diagrams (OPDs) and Supplemental Official Block Diagrams (SOBDs), available on the web in pdf format, serve as the legal definition for BOEM offshore boundary coordinates and area descriptions.