Natural Resources Conservation Service (NRCS) GIS Data
A wide range of GIS data resources are available from the USDA Natural Resources Conservation Service. Highlights include the US General Soils Map (STATSGO2), SSURGO soils, and the National Resources Inventory (NRI) all of which are documented on this page.
Online Mapping, downloading, and data ordering of many NRCS GIS data layers are available from the Geospatial Data Gateway.
US General Soils (STATSGO2)
The US General Soil Map (STATSGO2) consists of "state general soil maps made by generalizing the detailed soil survey data. The level of mapping is designed to be used for broad planning and management uses covering state, regional, and multi-state area. The original STATSGO (stands for State Soil Geographic Database) data were revised and updated in 2006, and hence renamed. Contact Data Services if you need a copy of the original STATSGO data for North Carolina.
The Soil Survey Geographic (SSURGO) Data Base consists of 1:12,000 to 1:63,360 scale detailed local soils data. "SSURGO digitizing duplicates the original soil survey maps. This level of mapping is designed for use by landowners, townships, and county natural resource planning and management. The user should be knowledgeable of soils data and their characteristics."--(NRCS site).
SSURGO data is downloadable in various formats and projections for most of the US (status graphic) from:
- Web Soil Survey - View maps and data online for small areas of interest. First, you must create an "Area of Interest" to work with. Download soils GIS data for any specified location.
- Libraries' SSURGO2 Geodatabases for NC Counties
It is recommended that you use SSURGO2 data only from one of these two sites because they have been certified by NRCS for accuracy. Note that you will not be able to download the data immediately from the Soil Data Mart, but will instead have your request put into a queue, which may take several minutes or possibly days to get to your request. Metadata are also available for each dataset and extensive documentation is available.
- If you are using ArcGIS, working with SSURGO data is MUCH easier by using the NRCS Soil Data Viewer. This is an ArcMap extension that handles downloading the data and automatically makes soil mapping unit attribute joins to the appropriate databases. Analyses and report generation has been made very simple with this extension.
- Older soils data that were digitized by NC CGIA (status graphic) are available in ArcInfo Coverage format and shapefiles on the Geodata server (see the Detailed Data Listing and additional CGIA data).
Other NRCS Data Resources
The National Resources Inventory "...is a statistically based sample of land use and natural resource conditions and trends on U.S. nonfederal lands. It is the most comprehensive database of its kind ever attempted anywhere in the world" (NRCS). Since 1982, the NRI was conducted every 5 years; but, beginning with 2001, it is conducted annually.
Two CD-ROM products have been released of the NRI and are available from DH Hill Library:
According to the NRI website, annual inventory data is only available via the website (limited summary) or the NRI Online Analysis System used by NRI Coordinators.