Geographic Coordinate Database (GCDB)
Bureau of Land Management's Geographic Coordinate Data Base of The Public Land Survey System
North Dakota Pilot Project
The North Dakota GCDB project was kicked off at a meeting in August 2003. As an outcome of that meeting Golden Valley County and Billings County were selected as pilot counties to collect GCDB data and to demonstrate the functionality of the data. Since that time, some training has occurred and there has been another meeting in June 2004. The two counties are now working to integrate their parcel data with the GCDB.
The following information is provided to help you to evaluate the GCDB for incorporation into GIS applications for community business needs.
What is the GCDB?
The Geographic Coordinate Data Base (GCDB) http://www.blm.gov/wo/st/en/prog/more/gcdb.html is the graphical depiction of the Public Land Survey System (PLSS). The GCDB is the foundation for parcel-based records systems to support land management decisions and is critical to the utilization of automated systems by Federal, State, and local government agencies, Tribal governments, the private sector, and others. The source of data collected for GCDB are BLM survey records (such as official plats and field notes), geodetic control information, and survey records collected by State, local and Tribal governments. The resulting information that is produced includes land boundaries of townships, sections, lots and survey corners, and legal descriptions.
How is the GCDB used and where can I get the data?
The GCDB data base is used by the BLM, other Federal agencies, States, Tribes, local governments, and others, as a common framework for collection of information and decisions related to the land such as title and land ownership, use authorizations; location of facilities such as buildings, roads and pipelines; stipulations for oil and gas development and other types of information. This comprehensive GIS information is not available from any other source. Please visit the GCDB National Home Page for more information and to download this data.
Current and Future GCDB Coverage
An overall view of the current GCDB coverage in the western United States can be found on the National Integrated Lands System, Land Survey Information Site.
What are the Benefits of Using the GCDB?
The GCDB database is a critical tool in developing and utilizing automated information systems and data that are interchangeable between various jurisdictions, to allow effective community planning and collaborative decision-making. Decision makers are relying more heavily upon digital data to examine management alternatives and measure potential impacts on the economy. Community leaders can use GCDB to support a multitude of business needs including homeland security and emergency response, revenue management, economic development, and maintaining livable communities. Federal and State governments need the same information for energy leasing and mineral sales, recreation, environmental analysis, planning, and environmental assessment. The GCDB provides the capability to georeference any item or object which has a geographical or spatial description. This includes pipelines, rights-of-way, oil and gas wells, telecommunication corridors, and other items related to critical infrastructure.
To address multiple related land issues, the Western Governors Association has strongly endorsed the GCDB through the WGA sponsored Western Cadastral Data and Policy Forum and the Western Governors Geographic Information Council.
Why is the Bureau of Land Management Creating the GCDB?
The Bureau of Land Management has been directed by the U.S. Office of Management and Budget (OMB) to standardize and produce a data base of geographic coordinates of the Public Land Survey System (PLSS) into seamless data across the United States.
This direction is provided for under OMB Circular No. A-16, entitled Coordination of Geographic Information and Related Spatial Data Activities.
This data is collectively titled the Geographic Coordinate Data Base (GCDB). The GCDB is part of a national spatial data asset known as the National Spatial Data Infrastructure as identified in OMB Circular No. A-16. The GCDB provides a standardized seamless coverage of the PLSS that crosses federal, state, county and local jurisdictional boundaries over the western United States. Because it is parcel based and attributed to the legal land description of the parcel, it is easily linked and integrated with other lands records data.
How is the GCDB different from other PLSS data such as the digitized USGS 1:24000 scale maps?
Here's a summary of GCDB advantages over other PLSS data:
- The GCDB is based upon survey measurements from official records; not digitized or scaled from map sources
- Subdivision of parcels based upon survey practice and rules
- Parcel based with Legal Land Description attributes
- Seamless coverage of the PLSS (NSDI) LSIS
- Standardized, Crosses jurisdictional boundaries of federal, state and local governments
- Complies with OMB Circular A-16, and Federal Geographic Data Committee Standards
- Endorsed by Western Governor s Association, the National Association of Counties, and the national strategy for the Presidents Geospatial One Stop E-Gov Initiative
- More easily integrated and linked with other data
- Maintenance and distribution of data is centralized by BLM at the Land Survey Information Site in Denver
Establishing and maintaining (updating) GCDB data as the standard is in accordance with recommendations from the Western Governors' Association, the National Association of Counties, and the national strategy for the Presidents Geospatial One Stop E-Gov initiative. Much effort has been put into creating and implementing data standards which are necessary to facilitate seamless sharing of spatial data between geographic and political boundaries.
The source data for the GCDB is from legal records containing survey measurements and legal descriptions and is computed according to survey practice and survey rules. The data is updateable as new surveys are created.
Components of the Geographic Coordinate Data Base (GCDB)
Each township, section, lot and parcel of the PLSS contained in GCDB is computed from record survey measurements taken from the official GLO plats and notes and private surveys. Each polygon contains the proper legal description attribute. The accuracy of each computed point is derived from a least squares adjustment routine and is available for review. Because the data is computed from record survey measurements, it can be revised and maintained as new surveys are created. Each township contains the required metadata as directed by the Federal Geographic Data Committee (FGDC) standards. Maintenance and distribution of the GCDB is centralized by the BLM from the National Integrated Lands System, Land Survey Information Site located in Denver Colorado.
Why is the BLM involving federal, Tribal, state, county and the private sector in the GCDB?
The BLM is currently involving stakeholders from the federal, Tribal, state, county, and private sector to develop collaborative partnerships for efficient collection and sharing of GCDB coverage in North Dakota. The goal of these partnerships is to:
- eliminate duplication of data
- avoid redundant expenditures of resources for cost effective data collection and maintenance
- create a single standardized, seamless data coverage of the PLSS