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Description of Gridded Soil Survey Geographic (gSSURGO) Database

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Introduction
  • User Guide (PDF; 10.7 MB)
FY2015 Release Notes
VALU Table Database
Metadata
Recommended Data Citations
Technical Information
Ordering Information
Sample gSSURGO Map Themes

Potential Wetland Soil Landscapes for Central Minnesota Sandy Outwash Region of Minnesota (MLRA 91A).

Introduction

Gridded SSURGO (gSSURGO) is similar to the standard USDA-NRCS Soil Survey Geographic (SSURGO) Database product but in the format of an Environmental Systems Research Institute, Inc. (ESRI®) file geodatabase. A file geodatabase has the capacity to store much more data and thus greater spatial extents than the traditional SSURGO product. This makes it possible to offer these data in statewide or even Conterminous United States (CONUS) tiles. gSSURGO contains all of the original soil attribute tables in SSURGO. All spatial data are stored within the geodatabase instead of externally as separate shapefiles. Both SSURGO and gSSURGO are considered products of the National Cooperative Soil Survey (NCSS) partnership.

The gridded SSURGO (gSSURGO) dataset was created for use in national, regional, and statewide resource planning and analysis of soils data. The raster map layer data can be readily combined with other national, regional, and local raster layers, including the National Land Cover Database (NLCD), the National Agricultural Statistics Service (NASS) Crop Data Layer (CDL), and the National Elevation Dataset (NED).

The gSSURGO Database is derived from the official Soil Survey Geographic (SSURGO) Database. SSURGO generally has the most detailed level of soil geographic data developed by the National Cooperative Soil Survey (NCSS) in accordance with NCSS mapping standards. The tabular data represent the soil attributes and are derived from properties and characteristics stored in the National Soil Information System (NASIS). The gSSURGO data were prepared by merging the traditional vector-based SSURGO digital map data and tabular data into statewide extents, adding a statewide gridded map layer derived from the vector layer, and adding a new value-added look up table (valu) containing “ready to map” attributes. The gridded map layer is in an ArcGIS file geodatabase in raster format. The raster and vector map data have a statewide extent. The raster map data have a 10-meter cell size that approximates the vector polygons in an Albers Equal Area projection. Each cell (and polygon) is linked to a map unit identifier called the map unit key. A unique map unit key is used to link the raster cells and polygons to attribute tables.

Fact Sheet (PDF; 445 KB)
User Guide, version 1.1 (PDF; 10.7 MB)

  • Errata (page 80, Appendix:  row 54, column D  - Root Zone Depth Description)

    Corrected to read “Root zone depth is the depth within the soil profile that commodity crop (cc) roots can effectively extract water and nutrients for growth. Root zone depth influences soil productivity significantly. Soil component horizon criteria for root-limiting depth include: presence of hard bedrock, soft bedrock, a fragipan, a duripan, sulfuric material, a dense layer, a layer having a pH of less than 3.5, or a layer having an electrical conductivity of more than 16 dS within the component soil profile. If no root-restricting zone is identified, a depth of 150 cm is used to approximate the root zone depth (Dobos et al., 2012). Root zone depth is computed for all map unit major earthy components (weighted average). Earthy components are those soil series or higher level taxa components that can support crop growth (Dobos et al., 2012). Major components are those soil components where the majorcompflag = 'Yes' (SSURGO component table). NULL values are presented where data are incomplete or not available”.


FY2015 Release Notes

The FY2015 Gridded Soil Survey Geographic (gSSURGO) Database was released on February 23, 2015. These data are derived from a December 1, 2014, snapshot of the Soil Data Mart database (FY2015 Soil Survey Geographic Database or SSURGO source). These new data are available in both state-wide tiles and the Conterminous U.S. (CONUS) at a resolution of 10 meters in a file geodatabase format. Additional resolutions of 30 meters and 90 meters are available for the Conterminous US (CONUS) gSSURGO database. Each gSSURGO dataset includes all SSURGO vector and attribute tables (with relates) plus the map unit raster layer. Also included is the FY2015 National gSSURGO Value Added Look Up (VALU) Table Database that provides ready-to-map themes such as available water storage and soil organic carbon in (11) standard depth layers and zones; crop root zone depths; available water storage in the crop root zone; drought vulnerable soil landscapes; and potential wetland soil landscapes. A gSSURGO User Guide is also included. These data are available for download or portable media order from the USDA Geospatial Data Gateway.  A new release is planned for the second quarter of each Federal fiscal year. 


Value Added Look Up Table Database

This dataset is called the National Value Added Look Up (valu) Table database. The valu1 table resides in the valu database and is comprised of 57 pre-summarized or “ready to map” attributes derived from the official SSURGO database. These attribute data are pre-summarized to the map unit level using best-practice generalization methods intended to meet the needs of most users. The generalization methods include map unit component weighted averages and percent of the map unit meeting a given criteria. These themes were prepared to better meet the mapping needs of users of soil survey information and can be used with both SSURGO and gridded SSURGO (gSSURGO) datasets. Below is a partial list of the data found in the valu1 table.

  • Soil organic carbon - weighted average (g C/m2)
     
  • Available water storage - weighted average (mm)
     
  • National Commodity Crop Productivity Index (NCCPI) Version 2 - weighted average index for major components (Dobos, Sinclair, and Robotham, 2012)
     
  • Root-zone depth of commodity crops - weighted average (cm) major components (Dobos et al., 2012)
     
  • Available water storage within the root-zone depth - weighted average (mm) major components
     
  • Drought-vulnerable soil landscapes (The map unit is identified as either drought vulnerable or not drought vulnerable. Drought-vulnerable soil landscape map units have 152 millimeters (6 inches) or less root zone available water storage for major components.)
     
  • Potential wetland soil landscapes (PWSL Version 1) - percentage of the map unit that meets the criteria for a potential wetland soil landscape (see table metadata for detailed criteria)


Metadata

SSURGO/STATSGO2 Structural Metadata and Documentation

The metadata page for SSURGO/STATSGO2 contains information about the database structure and contents that are also relevant to gSSURGO.


Recommended Data Citations

The Citation for gSSURGO

State Tile

Soil Survey Staff. Gridded Soil Survey Geographic (gSSURGO) Database for State name. United States Department of Agriculture, Natural Resources Conservation Service. Available online at http://datagateway.nrcs.usda.gov/. Month, day, year (FYyear official release).

Conterminous U.S. Tile

Soil Survey Staff. Gridded Soil Survey Geographic (gSSURGO) Database for the Conterminous United States. United States Department of Agriculture, Natural Resources Conservation Service. Available online at http://datagateway.nrcs.usda.gov/. Month, day, year (FYyear official release).

National Collection of Tiles

Soil Survey Staff. Gridded Soil Survey Geographic (gSSURGO) Database for the United States of America and the Territories, Commonwealths, and Island Nations served by the USDA-NRCS. United States Department of Agriculture, Natural Resources Conservation Service. Available online at http://datagateway.nrcs.usda.gov/. Month, day, year (FYyear official release).
 

The Citation for the National Value Added Look Up (valu) Table Database

Soil Survey Staff. National Value Added Look Up (valu) Table Database for the Gridded Soil Survey Geographic (gSSURGO) Database for the United States of America and the Territories, Commonwealths, and Island Nations served by the USDA-NRCS. United States Department of Agriculture, Natural Resources Conservation Service. Available online at http://datagateway.nrcs.usda.gov/. Month, day, year (FYyear official release).
 

Citation Examples

The following examples are for the FY2015 gSSURGO dataset for the State of West Virginia. Such citations should appear in the reference section of your document.

State Tile

Soil Survey Staff. The Gridded Soil Survey Geographic (gSSURGO) Database for West Virginia. United States Department of Agriculture, Natural Resources Conservation Service. Available online at http://datagateway.nrcs.usda.gov/. December 1, 2014 (FY2015 official release).

Conterminous U.S. Tile

Soil Survey Staff. Gridded Soil Survey Geographic (gSSURGO) Database for the Conterminous United States. United States Department of Agriculture, Natural Resources Conservation Service. Available online at http://datagateway.nrcs.usda.gov/. December 1, 2014 (FY2015 official release).

National Collection of Tiles

Soil Survey Staff. Gridded Soil Survey Geographic (gSSURGO) Database for the United States of America and the Territories, Commonwealths, and Island Nations served by the USDA-NRCS. United States Department of Agriculture, Natural Resources Conservation Service. Available online at http://datagateway.nrcs.usda.gov/. December 1, 2014 (FY2015 official release).
 

The following example is for the National Value Added Look Up (valu) Table Database. Such citations should appear in the reference section of your document.

National Value Added Look Up (valu) Table Database

Soil Survey Staff. National Value Added Look Up (valu) Table Database for the Gridded Soil Survey Geographic (gSSURGO) Database for the United States of America and the Territories, Commonwealths, and Island Nations served by the USDA-NRCS. United States Department of Agriculture, Natural Resources Conservation Service. Available online at http://datagateway.nrcs.usda.gov/. December 1, 2014 (FY2015 official release).
 

See http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/geo/?cid=nrcs142p2_053368 for recommended citations for other data provided by the USDA Natural Resources Conservation Service and the National Cooperative Soil Survey.


Technical Information

To obtain technical information about the use of soil data, please contact the NRCS State Soil Scientist in your state, or:

Soils Hotline Staff
Telephone: (402) 437-5378 (Steve Speidel) or (402) 437-5379 (Tammy Cheever)


Ordering Information

gSSURGO can be obtained as one or more statewide tiles via free download from the USDA-NRCS Geospatial Data Gateway (GDG) website located at http://datagateway.nrcs.usda.gov/.  Depending on file size, the data may also be available on CD-ROM or DVD. The cost for a single CD-ROM is $50; the cost for a single DVD is $100.

The conterminous U.S. and/or national collection of gSSURGO data can be obtained by contacting the USDA-NRCS National Geospatial Center of Excellence (NGCE) representative Rosemary Rivera (rosemary.rivera@ftw.usda.gov) or by phoning (817) 509-3371. The cost for this service is $250.  The customer provides the external storage device and also pays shipping costs.


Sample gSSURGO Map Themes

Root Zone Depth for Commodity Crops (PDF; 9.31 MB)
Potential Wetlands Soil Landscapes (PDF; 6.63 MB)