Branch of Spatial Records, Division of Geographic Sciences, 20040615, Spatial Data Management System Corner Layer, Surveyed Corners, Alaska.
This is a Vector data set. It contains the following vector data types (SDTS terminology):
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000027778. Longitudes are given to the nearest 0.000027778. Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257222.
PIDs are a numbering system for the PLSS rectangular grid, adopted by the BLM GCDB program nationally. PIDs are a six digit integer. The PID identifies the relative position of a point on the rectangular grid, within a given township. 100100 represents the southwest corner of a township. 700700 represents the northeast corner.
PIDs are a numbering system for the PLSS rectangular grid, adopted by the BLM GCDB program nationally. PIDs are a six digit integer. The PID identifies the relative position of a point on the rectangular grid, within a given township. 100100 represents the southwest corner of a township. 700700 represents the northeast corner.
Serial value assigned by the SDMS data collection system
PIDs are a numbering system for the PLSS rectangular grid, adopted by the BLM GCDB program nationally. PIDs are a six digit integer. The PID identifies the relative position of a point on the rectangular grid, within a given township. 100100 represents the southwest corner of a township. 700700 represents the northeast corner.
| Value | Definition |
|---|---|
| CTL | Control |
| COR | Regular corner |
| SYS | System-generated corner |
PIDs are a numbering system for the PLSS rectangular grid, adopted by the BLM GCDB program nationally. PIDs are a six digit integer. The PID identifies the relative position of a point on the rectangular grid, within a given township. 100100 represents the southwest corner of a township. 700700 represents the northeast corner.
PIDs are a numbering system for the PLSS rectangular grid, adopted by the BLM GCDB program nationally. PIDs are a six digit integer. The PID identifies the relative position of a point on the rectangular grid, within a given township. 100100 represents the southwest corner of a township. 700700 represents the northeast corner.
PIDs are a numbering system for the PLSS rectangular grid, adopted by the BLM GCDB program nationally. PIDs are a six digit integer. The PID identifies the relative position of a point on the rectangular grid, within a given township. 100100 represents the southwest corner of a township. 700700 represents the northeast corner.
Values as determined from the survey record.
Values as determined from the survey record.
Each survey has an implied reliability based on the perceived accuracy of the control used. Each corner in the survey then, inherits the survey's implied reliability.
| Value | Definition |
|---|---|
| N27 | North American Datum 1927 |
Each survey has an implied reliability based on the perceived accuracy of the control used. Each corner in the survey then, inherits the survey's implied reliability.
Each survey has an implied reliability based on the perceived accuracy of the control used. Each corner in the survey then, inherits the survey's implied reliability.
Each survey has an implied reliability based on the perceived accuracy of the control used. Each corner in the survey then, inherits the survey's implied reliability.
Source ID is the system-generated primary key for a Source.
Survey organization as identified from survey records.
Corner Legal Description is a system-generated field constructed by concatenating all the corner aliases (corner-land descriptions) to form a single narrative style description of the corner.
| Range of values | |
|---|---|
| Minimum: | 49.657833099365234375 |
| Maximum: | 71.37645721435546875 |
| Units: | decimal degrees |
| Range of values | |
|---|---|
| Minimum: | -179.9916534423828125 |
| Maximum: | 179.9892730712890625 |
| Units: | decimal degrees |
| Range of values | |
|---|---|
| Minimum: | 49.657833099365234375 |
| Maximum: | 71.37645721435546875 |
| Units: | decimal degrees |
| Range of values | |
|---|---|
| Minimum: | -179.9916534423828125 |
| Maximum: | 179.9892730712890625 |
| Units: | decimal degrees |
Corner Legal Description is a system-generated field constructed by concatenating all the corner aliases (corner-land descriptions) to form a single narrative style description of the corner.
Elevation as determined from survey records.
The source of the measurement.
A system field to identify a land unit that controls the corner's position
A system field that tracks whether a position may be updated.
| Value | Definition |
|---|---|
| VALID | Corner describes the geometry of one or more land units. All requisite relationships exist. |
| ORPHAN | Corner does not describe the geometry of any land unit, but remains related to one or more land units. An Orphan corner may become Valid if is utilized to describe a land unit's geometry. If an Orphan corner is not used within a certain timeframe, it is administratively removed from the system. |
| PENDING | Corner that has no relationships to any land, but may become a Valid corner at some point. Examples of this are raw data from other organizations, imported control stations, etc. |
| ZOMBIE | Corner has no relationships with any land, and is not marked as Pending. A corner will not by explicitly labeled by this status, but will be apparent during an administrative search. Zombie corners should be immediately removed from the system. |
Original set date from survey records.
Current date from survey records.
Estimated deviation along the y-axis.
Estimated deviation along the x-axis.
User ID of person that entered the original data for this record.
System date.
User ID of the person that modified the data for this record.
System date.
System generated id.
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
(907) 271-3237 (voice)
(907) 271-4549 (FAX)
Dennis_Walworth@ak.blm.gov
This dataset was created to provide an accurate, seamless portrayal of the PLSS network, based upon survey records. The dataset is intended for use as a base layer for mapping purposes, and as a framework for the portrayal of land ownership
Person who carried out this activity:
(907) 271-3237 (voice)
(907) 271-4549 (FAX)
Dennis_Walworth@ak.blm.gov
A. Attribute records are input from approved survey records - this process results in a 100% review of existing survey records. Errors in existing survey records are forwarded to the Review Section for corrections.
B. Spatial Data Management System validation:
1. Self-validation through data collection application
a. SDMS data collection application creates legal description from well-known alias names within the context of the land being collected;
b. Geometry Checks: can't modify geometry in one land without also changing geometry of adjacent land;
c. Automation of input processes ensures standardization of things like legal land descriptions and corner descriptions.
d. Spatial data are generated by position calculations from the survey record attributes. All inaccuracies found in the spatial features are fixed in the attribute record information and then spatial data is re-generated. An error is never "fixed" by spatial edits.
e. All input is validated by the system to verify observance of Cadastral Survey business rules and integrity of the data. For instance, no two corners can share the same position. A corner cannot exist in the system more than once. There cannot be significant breaks in the bearing along a fixed boundary, etc.
2. Print out and review reports:
a. Print land, boundary, tie, and corner reports to review for accuracy against survey record;
b. Establish limit of closure and run closure report against the established limit of closure.
3. Geometry is exported in the largest possible 'network' possible. Networks are defined as those land units that are adjacent to one another or are connected through ties to nearby land units. Edge-matching of adjacent land units are resolved at the coordinate level through the data collection application.
a. Special Survey land unit networks are defined as the largest possible 'grouping' of land units (defined by adjacency or by tie).
b. Rectangular land unit networks are defined by township. Edge-matching of townships are defined at the coordinate level within the data collection application.
C. Spatial validation:
1. Review land spatially - check arc/info generate "shape" against existing land net;
2. Review land net imported into SDE layer against existing SDE land net;
3. Spatial errors are forwarded to data collection staff for correction within the SDMS application. Spatial data is never edited spatially.
D. Spatial land unit polygon completion:
1. Special Survey land unit polygons are usually 'self-contained' land descriptions. These descriptions include metes and bounds descriptions of all boundaries, including hydrographic boundaries.
2. Rectangular survey land unit polygons may be composites of both rectangular and non-rectangular descriptions (hydrography meanders).
Data collection is complete as of the date of publication. This metadata describes a snapshot of the data, current as of the date of publication.
All fields in the corner table are system-generated by the SDMS data collection system. The sole exception is the cor_lat_meas and the cor_lon_meas fields. These fields may be used when the source coordinates are known for the point-of-beginning the this corner is defined as the point-of-beginning.
Corners positions are based on either known or derived corners (points) determined through geodetic calculations. Corners are used to construct boundaries. The resulting boundaries are used to construct polygons.
Are there legal restrictions on access or use of the data?
- Access_Constraints:
- Discretionary, contains no sensitive information - generally considered releaseable.
- Use_Constraints:
- Accuracy published on or derived from BLM's official survey records. Please refer to BLM's official survey records for specific bearing and distance information.
Any hardcopies or published datasets using these data shall clearly indicate their source. Any users wishing to modify the data are obligated to describe the types of modifications they have performed. User specifically agrees not to misrepresent the data, nor to imply that changes made were approved or endorsed by the BLM. Any discrepancies or errors in this data should be reported to John_Montgomery@ak.blm.gov
(907) 271-5799 (voice)
(907) 271-4549 (FAX)
tvarner@blm.gov
Downloadable Data
No warranty is made by the Bureau of Land Management as to the accuracy, reliability, or completeness of these data for individual use or aggregate use with other data.
(907) 271-5799 (voice)
(907) 271-4549 (FAX)
Tim_Varner@ak.blm.gov
Generated by mp version 2.9.2 on Thu Jan 10 09:45:01 2008