U.S. DEPARTMENT OF THE INTERIORBUREAU OF LAND MANAGEMENT
Geographic Coordinate Data Base (GCDB)
GCDB PLSS Data References More info - Contact
More info - Contact
Who uses GCDB data? Since the 1990’s the GCDB flat files have been used by Federal agencies for making maps using computer-aided drafting applications. Soon many land surveyors began using the GCDB flat files to help them locate survey corners on the ground. Over time, the GCDB data became available via the Internet in geographic information system (GIS) formats and many local governments and private companies began using the GCDB in their in-house GIS applications. During the last few years geospatial products like the Cadastral National Spatial Data Infrastructure (CADNSDI) file geodatabases have been developed and distributed on-line. Today the typical GCDB user might be anybody with a global positioning system (GPS) unit, a smart phone or an Internet connection and an interest in maps.
Tell me more. BLM began collection of the geographic coordinate information in 1989 and the data collection effort continues today. The best positions for the survey points are determined by:
To find out more about GCDB file formats and data elements check out the GCDB User’s Manual and the GCDB Standards web page.
Which GCDB format is best? Where available, the best GCDB datasets for GIS/geospatial work are the CADNSDI file geodatabases. The CADNSDI databases conform to the newest Federal Geographic Data Committee (FGDC) guidelines for geospatial data and contain the most up-to-date GCDB data. In areas where the GCDB data has NOT been collected, the CADNSDI datasets are supplemented with PLSS data from alternate sources. The resulting seamless (or almost seamless) statewide datasets are reviewed by the PLSS data steward with jurisdiction and approved as the best available PLSS data before the datasets are published.
Where can I get the data? CADNSDI file geodatabases for Arizona, California, Colorado, Idaho, Montana/North Dakota, Nevada, New Mexico, Utah and Wyoming are available for download from the PLSS Data Download site on the GeoCommunicator Download Public Land Survey System (PLSS) Data web site. CADNSDI databases for Oregon and Washington are expected to be available soon.
The legacy (before CADNSDI) GCDB data complies with the previous FGDC guidelines for geospatial data. This data, along with PLSS data from alternate sources, can be downloaded by state, county or interactive selection of your desired area-of-interest in shapefile GIS format. Additionally, points can be exported in KML (for Google Earth), GPX, List and GeoRSS file formats using the interactive selection method. The legacy data is also available on GeoCommunicator''s Interactive maps or as Map Services in ArcIMS (image and feature), WMS and ArcGIS formats. GeoCommunicator's GeoCoder provides a convenient way to convert latitude and longitude to PLSS land descriptions and vice-versa. Keep in mind that the legacy data has not been updated since December 2009 because BLM has been focusing on development of the CADNSDI datasets.
Many of the BLM state offices have posted their GCDB flat files on their state office websites. Links to these websites are provided on the GCDB Offices page.