OCS Aliquot 16ths Polygons - 3rd Division

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.等分地块（aliquot）源自外大陆架（Outer Continental Shelf, OCS）区块，具体方式为将每个区块划分为16个等分单元，该细分方式可实现近海能源租赁中更精细的边界划定。这些多边形地块会被裁剪至《淹没土地法》边界与大陆架边界范围内。等分地块除附带其父级标定编号与OCS区块编号外，还会被赋予字母后缀（例如NK18-02、6822F）。完整OCS区块尺寸为4800×4800米，而单个等分地块尺寸为1200×1200米。沿联邦/州级OCS边界与通用横轴墨卡托（Universal Transverse Mercator, UTM）分带边界分布的等分地块会被进一步裁剪，尺寸更小。仅官方或法律用途需使用最新发布的纸质或PDF版官方标定等分地块图（Official Protraction Aliquot Diagram, OPAD）。本数据集初始采用适配的北美大地基准83通用横轴墨卡托（NAD83 UTM）或北美大地基准27通用横轴墨卡托/州平面坐标系（NAD27 UTM/SPCS）投影，后被重投影至大地坐标系统WGS84（EPSG 4326），以用于美国海洋能源管理局（Bureau of Ocean Energy Management, BOEM）的企业地理信息系统（GIS）管理。但本数据集集合中的此服务采用WGS 1984 Web墨卡托辅助球面投影（EPSG 3857）发布。由于地理信息系统的投影与拓扑功能可能会变更或简化坐标信息，本数据集并非精确边界的官方备案文件。本数据集仅可用于制图用途，不得用于面积计算。