The Soil Survey Geographic (SSURGO) data is the most detailed level of digital soils data available from the Natural Resources Conservation Service (NRCS). A SSURGO data set consists of map data, attribute data and metadata. The Map extent for a SSURGO data set is a soil survey area, which may consist of a county, multiple counties, or parts of multiple counties.
Before a soil survey area can be digitized, the mapping base must meet national map accuracy standards. Acceptable bases are either orthophotoquadrangles or 7.5-minute quadrangles. If a survey area was originally mapped on another base, the lines area manually transferred to an acceptable base. Digitizing is done by line segment (vector) format in accordance with NRCS digitizing standards and specifications. Soil boundaries ending at quad neat lines are matched exactly to adjoining soil boundaries within a survey area.
For certification, a SSURGO data set must meet all standards and specifications as described in the NRCS National Soil Survey Handbook (NSSH). This includes a 100 percent digital data review by a certification center. After a data set is certified, it is archived and distributed through the NRCS National Cartography and Geospatial Center (NCG) in Ft. Worth, TX.