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The Tobin BLM Digital
Survey is a spatial database representing the Bureau
of Land Management’s (BLM) digital Public Land
Survey System (PLSS). The data is made available to
the public from the BLM as the Geographic Coordinate
Database (GCDB). The BLM collects this information on
a township level and has been continually collecting
geographic information since 1989. The source data used
in their collection process are official BLM survey
records and corresponding geodetic control information.
The BLM collection process consists of delineating a
township and section land unit grid by determining the
geographic location of survey boundaries. An official
land description is then assigned to each land unit.
GCDB data is made available
as ARC/INFO township coverages in an export file format
(e00 file). Tobin downloads this data at the township
level by state from the GCDB website. This data is
then converted to a Tobin format, one similar to Tobin’s
Superbase product. The Tobin conversion process keeps
the integrity of the digital survey as a BLM source.
The final product Tobin will offer will be an accurate
spatial representation of the BLM’s PLSS.
For
a more detailed description of the BLM collection
process,
visit the BLM’s GCDB website.
•
Digital product represents the BLM Digital Survey.
• Same structure as the Tobin SuperBase®
Survey.
• Edge matched within the data set by Tobin.
• Provides comparison-background to Tobin Superbase
Survey.
• Data Set includes Polygons, Attributes, and
Annotations for Meridians,
Township and Range, and Sections
•
The definitive data set to compare Federal Surveying
efforts with the Oil and Gas
Industry Standard, Tobin SuperBase.
• Differences with TobinSuperBase can alert
users that additional title work may be required.
• Since the data is digital and includes a database
of attributed data it can be formatted for
users of GIS, mapping, and/or CAD applications.
• Data is updated quarterly, based on Federal
changes.
The
data that is downloaded from the GCDB are ARC/INFO
coverages that spatially depict land areas and survey
lines for a single township. The ARC/INFO feature
classes available with these coverages are polygon,
regions, arcs, node, and labels. Polygons will be
the primary feature class the conversion process will
be processing. The polygonal coverage is a township
survey at the quarter section level with every polygon
representing a quarter section.
•
Arizona
• California
• Colorado
• Idaho
• Montana
• Nevada
• New Mexico
• North Dakota
• Oregon
• Utah
• Washington
• Wyoming
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The BLM has
stated that the geographic coordinates of this data
set have no legal significance and should not be used
as a substitute for a legal boundary survey. The BLM
also states that this digital survey can be used for
record keeping, mapping, and planning purposes. This
product that Tobin created from the BLM is a useful
tool that can be used as reference for determining
PLSS boundaries as how the BLM delineates them.
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