This data set contains the Submerged Lands Act (SLA) boundary (also known as State Seaward Boundary (SSB), or Fed State Boundary) in ESRI shapefile format for the BOEM Alaska Region. The SLA boundary defines the seaward limit of a state's submerged lands and the landward boundary of federally managed OCS lands. In the BOEM Alaska Region it is projected 3 nautical miles offshore from the baseline. Further information on the SLA and development of this line from baseline points can be found in OCS Report MMS 99-0006: Boundary Development on the Outer Continental Shelf http://www.boem.gov/BOEM-Newsroom/Library/Publications/1999/99-0006-pdf.aspx. Due to slight differences in process and purpose, NOAA's 3 nautical mile line depicted on its charts may differ in some areas from the SLA boundary depicted on BOEM maps and OPDs and should not be confused with the SLA boundary. Therefore this boundary is the only boundary that should be used to depict state/federal seperation of jurisdiction for submerged lands. 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 SLA boundary. The Official Protraction Diagrams (OPDs) and Supplemental Official OCS Block Diagrams (SOBDs) serve as the legal definition for offshore boundary coordinates and area descriptions.
The SLA boundary and other cadastre information the BOEM produces are generated in accordance with 30 Code of Federal Regulations (CFR) 256.8 to support Federal land ownership and mineral resource management.
The BOEM is making its existing cadastre data available at http://www.boem.gov/Oil-and-Gas-Energy-Program/Mapping-and-Data/Index.aspx. These data include Official Protraction Diagrams (OPDs), and Supplemental Official OCS Block Diagrams (SOBDs) in pdf format, and digital spatial data in ArcGIS shapefile format.
publication date
The data was developed within the U.S. Government; no proprietary rights may be attached to them nor may they be sold to the U.S. Government as part of any procurement of digital data products or services.
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The file is believed to be free of topologic errors
The Alaska statewide SLA boundary and Limit of "8(g) Zone" are currently incomplete. It is incomplete in two different ways and in the following locations: 1. Unofficial boundaries within the Norton Basin Planning Area, St. George Basin, Kodiak Planning Area and the South West portion of North Aleutian Basin Planning Area lack state review. 2. The boundaries remain undeveloped within the Aleutian Arc Planning Area, Shumagin Planning Area and St. Matthew-Hall Planning Area. The solid SLA boundary and Limit of "8(g) Zone" lines depicted in the browse graphics reflect the official federal position for Submerged Lands Act and OCS Lands Act purposes. The areas of the fractional blocks abutting these lines have been determined and are as depicted on the Supplemental Official OCS Block Diagrams (SOBDs). Consult the SOBDs for official descriptions and approval dates. SOBDs have not been published for blocks adjoining the approximate short dashed SLA boundary and the Limit of "8(g) Zone". Coordinates and areal measurements for these blocks are not considered by BOEM to reflect an official federal position. Another way to tell if a boundary is official or unofficial is by going to the SLA and 8g attribute table and look at the BDRY_COV_S field. The 200801 (SLA) and 200802 (8g) attributes indicate an official boundary with state review. The 200811 (SLA) and 200812 (8g) attributes indicate an unofficial boundary lacking state review.
Coordinates for points forming the Submerged Lands Act boundary are calculated to 3 decimal places of a meter in the TIMS database. However, GIS functions which build topology, change projections, etc. may alter coordinate values. Furthermore, most of the Submerged Lands Act boundary consists of true arcs, but has been approximated by these shapefiles with straight line segments. For these reasons, these shapefiles are considered to be approximate and are NOT an OFFICIAL record.
Coordinates for points used to project the SLA boundary
In-house computer programs were used to project the SLA boundary at the appropriate distance from the baseline points. This was a planar projection done in Universal Transverse Mercator.
381 Elden St.
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Internal feature number.
ESRI
Feature geometry.
ESRI
From node in ESRI notation
To node in ESRI notation
Left polygon in ESRI notation
Right polygon in ESRI notation
Line length in ESRI coverage units
Internal ESRI number
Internal ESRI number
Region Code is the identifier used to identify the BOEM Outer Continental Shelf (OCS) Region.
Bureau of Ocean Energy Management
Boundary Type Code (S = Submerged Lands Act Boundary')
Bureau of Ocean Energy Management
Boundary Point Protraction Number
Bureau of Ocean Energy Management
Boundary Approval Date (day-month-year)
Bureau of Ocean Energy Management
Block Number the line segment is in
Bureau of Ocean Energy Management
Boundary Name Code
Bureau of Ocean Energy Management
Boundary Name Text
Bureau of Ocean Energy Management
Boundary Cover Sequence Number
Bureau of Ocean Energy Management
ESRI
Bureau of Ocean Energy Management
381 Elden St.
Mail Stop HM3120
As is. No responsibility is assumed for the correctness of this data.
381 Elden St
Mail Stop HM3120