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OCS Aliquot 16ths Polygons - 3rd Division

Published by Bureau of Ocean Energy Management | Department of the Interior | Catalog Last Checked: May 26, 2026 at 03:38 PM | Dataset Last Updated: March 31, 2026 at 12:00 AM
Aliquots are generated from Outer Continental Shelf (OCS) blocks by subdividing each block into 16ths, and this further subdivision allows for more detailed boundary delineation in offshore energy leasing. These polygons are clipped to the Submerged Land Act Boundary and Continental Shelf Boundaries. The aliquots use a letter designation in addition to their parent protraction number and OCS block number (e.g., NK18-02, 6822F). A full OCS block is 4800 x 4800 meters, while an aliquot measures 1200 x 1200 meters. Smaller, clipped aliquots are found along the Federal/State OCS boundary and along UTM zone borders. Only the most recently published paper or PDF versions of the Official Protraction Aliquot Diagram (OPAD) should be used for official or legal purposes.These data were created in the applicable NAD83 UTM or NAD27 UTM/SPCS Projection and re-projected to GCS WGS84 (EPSG 4326) for management in BOEM's enterprise GIS. However, this service in this collection has been published in WGS 1984 Web Mercator Auxiliary Sphere (EPSG 3857). Because GIS projection and topology functions can change or generalize coordinates, these data are NOT an OFFICIAL record for the exact boundaries. These data are to be used for Cartographic purposes only and should not be used to calculate area.

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Complete Metadata
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description <div style='text-align:Left;'><div><div><p><span>Aliquots are generated from Outer Continental Shelf (OCS) blocks by subdividing each block into 16ths, and this further subdivision allows for more detailed boundary delineation in offshore energy leasing. These polygons are clipped to the Submerged Land Act Boundary and Continental Shelf Boundaries. The aliquots use a letter designation in addition to their parent protraction number and OCS block number (e.g., NK18-02, 6822F). A full OCS block is 4800 x 4800 meters, while an aliquot measures 1200 x 1200 meters. Smaller, clipped aliquots are found along the Federal/State OCS boundary and along UTM zone borders. Only the most recently published paper or PDF versions of the Official Protraction Aliquot Diagram (OPAD) should be used for official or legal purposes.</span></p><p><span>These data were created in the applicable NAD83 UTM or NAD27 UTM/SPCS Projection and re-projected to GCS WGS84 (EPSG 4326) for management in BOEM's enterprise GIS. However, this service in this collection has been published in WGS 1984 Web Mercator Auxiliary Sphere (EPSG 3857). Because GIS projection and topology functions can change or generalize coordinates</span><span style='font-weight:bold;'>, these data are NOT an OFFICIAL record for the exact boundaries. These data are to be used for Cartographic purposes only and should not be used to calculate area.</span></p></div></div></div>
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issued 2026-05-21T14:34:12Z
keyword 
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  "BDS",
  "BOEM",
  "Boundary Delineation System",
  "Bureau of Ocean Energy Management",
  "Cadastre Theme",
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  "Marine Minerals",
  "OCS",
  "OMC",
  "OPDs",
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  "Offshore Marine Cadastre",
  "Oil",
  "Outer Continental Shelf",
  "Pacific",
  "Renewable Energy",
  "SOBDs",
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modified 2026-03-31T00:00:00Z
programCode 
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publisher 
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spatial -170.1213,-17.5553,-63.9056,48.5059
theme 
[
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]
title OCS Aliquot 16ths Polygons - 3rd Division

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