Public Land Survey to the Township Level for Wyoming, derived from BLM GCDB

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Metadata:

What does this data set describe?

Title:  Public Land Survey to the township level for Wyoming, derived from Bureau of Land Management Geographic Coordinate Database

 

Abstract: 

NOTE: This PLSS data is in the process of being replaced. The preferred, most current PLSS data can be found at http://www.blm.gov/wy/st/en/resources/public_room/gis/datagis/themes/gcdbgis.html

This dataset contains township and range information for all surveyed portions of Wyoming. A separate dataset contains the same information including section and tract information. Most of the data originated from Bureau of Land Management (BLM) GCDB (Geographic Coordinate Data Base) files, generated from legal surveys. The townships that were not collected for the GCDB where created from MOSS (Map Overlay Statistical System) GIS maps. These township where forced to edgematch with surrounding and/or adjacent GCDB data.

 

 

1. How should this data set be cited?

   Bureau of Land Management, Wyoming, 2002, Public Land Survey to the township level for Wyoming, derived from Bureau of Land Management Geographic Coordinate Database: Bureau of Land Management, Wyoming, Cheyenne, WY.

   Online Links:

   • Wyoming BLM GIS web page 

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -111
   East_Bounding_Coordinate: -104
   North_Bounding_Coordinate: 45
   South_Bounding_Coordinate: 41 

3.  What does it look like?

    

4. Does the data set describe conditions during a particular time period? 

   Calendar_Date: 2002

   Currentness_Reference: publication date

    

    

5. What is the general form of this data set?

    

6. How does the data set represent geographic features?  
   
   
   1. How are geographic features stored in the data set? 

      This is a Vector data set. 

   2. What coordinate system is used to represent geographic features?
      
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.01. Longitudes are given to the nearest 0.01. 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.
      The flattening of the ellipsoid used is 1/298.257.

7. How does the data set describe geographic features? 

   Entity_and_Attribute_Overview:

   Township datasets include these polygon attributes:

   dxf-text = Township and Range numbers combined (for quick queries) example: t35r117
   township = Township numbers, example: t35n
   range = Range Numbers, example: r117w
   Meridian = Prime Meridian number, 6 or 111

Entity_and_Attribute_Detail_Citation: none 

 Who produced the data set?

1. Who are the originators of the data set?   (may include formal authors, digital compilers, and editors)
   • Bureau of Land Management, Wyoming
     
      
2. Who also contributed to the data set? 

   Zack Puls

To whom should users address questions about the data? 

Larry Neasloney
Bureau of Land Management
5353 Yellowstone Rd
Cheyenne, Wyoming 82003
USA

307-775-6171 (voice)
larry_neasloney@blm.gov

Hours_of_Service: 8:00 - 5:00 MST 

Why was the data set created?

To provide base information about Wyoming's public survey system. May be used to locate legal descriptions to the township level.

 How was the data set created?

1. Where did the data come from? 

    GCDB (source 1 of 1)

   Bureau of Land Management, Wyoming, Publication_Information Publication_Place, Geographic Coordinate Database (GCDB):.

   Type_of_Source_Media: digital

   Source_Scale_Denominator: 24000

   Source_Contribution: Main source of data

    

2. What changes have been made? 

   
   Date: Unknown (change 1 of 2)

   This dataset is derived from the GDCB database. The following is an excerpt from the BLM's GCDB User's Manual (contact: Milbert Krohn, 307-775-6225). GCDB is generated from official BLM survey records and control coordinates of varying accuracy. GCDB data includes an estimate of the positional accuracy of the coordinates. This estimate is based on residual errors in adjusting survey data between known coordinates. This data allows the GIS user to determine suitability of the GCDB for various applications. GCDB data collection in Wyoming was initiated in September 1990. At that time, the Public Land Survey System Coordinate Computation Software (PCCS) was used for coordinate generation. In May of 1993, a second, and vastly improved, generation of GCDB software named Geographic Measurement Management (GMM) was released. GCDB is not a legal data base but rather attempts to maintain the spatial relationships as depicted on the legal survey records. The reliability of GCDB coordinates is dependent upon the quality of the data used to generate it which in many cases is poor. Given this, the user should be aware acreages which can be generated from GCDB data rarely reflect the legal acreages from the official survey records and are therefore invalid. 

Date: 19-Jan-1990-2002 (change 2 of 2)

Most township coverages originated from GCDB(Geographic Coordinate Data Base)files. Some error corrections such as undershoots and overshoots were performed using Autocad. The corrected township dxf files were converted to ARC/INFO coverages using the DXFARC command. No original GCDB point coordinates where moved during this process. The townships that where not collected for the GCDB where created from MOSS(Map Overlay Statistical System)GIS maps. These township were forced to edgematch with surrounding and/or adjacent GCDB coverages. Townships where joined into 100K tiles. Slivers between townships were removed with the ELIMINATE command in ARC/INFO or cartographic license was taken to complete edgematching. Generally points where moved less than 10 ground feet.

How reliable are the data; what problems remain in the data set? 

1. How well have the observations been checked? 

   Not available. Depends on the accuracy of the GCDB.  

2. How accurate are the geographic locations?  

   Generally, the user can assume the accuracy to be not less than 1:24000 or +- 50 ground feet. However,the following paragraph which is taken from the GCDB User's Guide on the Wyoming Geographic Information Advisory Council's GCDB Internet Page addresses limitations of GCDB data. These limitations also apply to the GIS/PLSS data layer.

   Wyoming's GCDB data was generated using the most recent official BLM survey records and in some cases private survey records provided by the Forest Service. The quality of these surveys vary widely. Correspondingly, the accuracy of the coordinates generated varies widely. GCDB is designed to maintain the spatial relationships as depicted on our official (legal) records. Any errors in the data are distributed in an unpredictable manner. Given this, the user must be aware that any acreages which this data may allow to be calculated are legally invalid. 

3. How accurate are the heights or depths?
   
   
    

4. Where are the gaps in the data? What is missing?

   Portions of the Wyoming level 5 and 6 survey have not been included in this dataset. Levels 5 and 6 have been surveyed but have not been translated to GCDB.

5. How consistent are the relationships among the observations, including topology?

   Data has been checked for topological consistency. There are no dangling Arcs, unlabeled polygons, or other topological errors.  

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None.

Use_Constraints: None. 

1. Who distributes the data set?  (Distributor 1 of 1)

   Data Manager
   Bureau of Land Management, Wyoming
   5353 Yellowstone
   Cheyenne, Wyoming 82001
   USA
   

   307-775-6171 (voice)
   larry_neasloney@blm.gov

2. What's the catalog number I need to order this data set?

    

3. What legal disclaimers am I supposed to read?

   The distributor shall not be held liable for improper or incorrect use of this data, based on the data quality section of this document. It is strongly recommended that this data is directly acquired from the distributor described above and not indirectly through other sources which may have changed the data in some way. 

4. How can I download or order the data?

   Data format:	ARCE (Arc/Info export) (version 7.0.4)
   Network links:	not available yet

   
   
   • Cost to order the date:  No fees are required for downloading the data that is on-line.

Who wrote the metadata?

Dates:

 

Last modified: 05-Nov-2002

Metadata standard:

FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

 Generated by mp version 2.4.13 on Mon Sep 18 10:09:06 2000