The Mapping & Boundary Branch performs mathematical offshore boundary location computations and prepares Official Protraction Diagrams (OPDs), 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.
This data set below contains Protraction Diagram (OPD) outlines in ESRI shapefile format from BOEM (2006). At higher latitudes (48-75 degrees) OPDs are 3 degrees wide. OPDs are further subdivided into blocks that are 4800 x 4800 meters on a UTM grid (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 grid. 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.
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 BOEM offshore boundaries. Only the coordinates shown on Official OPDs, CBDs, and SOBDs constitute an Official Record for offshore coordinate values. Further information on OPD's can be found in OCS Report MMS 99-0006 and the website reference below.
