STATSGO depicts information about soil features on or near the surface of the Earth. It is a digital general soil association map developed by the National Cooperative Soil Survey. It consists of a broad based inventory of soils and nonsoil areas that occur in a repeatable pattern on the landscape and that can be cartographically shown at the scale mapped. The soil maps for STATSGO are compiled by generalizing more detailed soil survey maps. Where more detailed soil survey maps are not available, data on geology, topography, vegetation, and climate are assembled, together with Land Remote Sensing Satellite (LANDSAT) images. Soils of like areas are studied, and the probable classification and extent of the soils are determined. The National Resources Inventory (NRI) is a scientifically-designed, longitudinal panel survey of the Nation's soil, water, and related resources designed to assess conditions and trends every five years. The NRI is conducted by the Natural Resources Conservation Service (NRCS), an agency of the U.S. Department of Agriculture (USDA), in cooperation with the Iowa State University (ISU) Statistical Laboratory.
The NRI STATSGO intersected data set has been compiled for use with the Geostac database in order to simplify pesticide risk assesement by providing a common data set upon which all stakeholders can perform anaylsis.
TBD
ground condition
STATSGO was designed primarily for regional, multicounty, river basin, State, and multistate resource planning, management, and monitoring. STATSGO data are not detailed enough to make interpretations at a county level. This soil survey product is not designed for use as a primary regulatory tool in permitting or citing decisions, but may be used as a reference source. When STATSGO data are overlayed with other data layers, such as land use data, caution must be used in generating statistics on the co-occurence of the land use data with the soil data. The composition of the STATSGO map unit can be characterized independently or the land use and for the soil component, but there are no data on their joint occurrence at a more detailed level. Analysis of the overlayed data should be on a map polygon basis. With STATSGO, additional political, watershed, or other boundaries may be intersected with the soil data. Although the composition of each political and watershed unit may be described in terms of the STATSGO map units, information is not available to assign the components to the boundary units with full accuracy. As with the land use categories, the analysis should be restricted to the classified components. For STATSGO, the approximate minimum area delineated is 625 hectares (1,544 acres), which is represented on a 1:250,000-scale map by an area approximately 1 cm by 1 cm (0.4 inch by 0.4 inch). Linear delineations are not less than 0.5 cm (0.2 inch) in width. The number of delineations per 1:250,000 quadrangle typically is 100 to 200, but may range up to 400. Delineations depict the dominant soils making up the landscape. Other dissimilar soils, too small to be delineated, are present within a delineation. For the NRI data set, results derived from the NRI data are estimates. All NRI results have some degree of uncertainty associated with them. Interpretation of NRI results requires an understanding of the amount of this uncertainty associated with each estimate, as well as an understanding of the inventory procedures. Since the NRI employs recognized statistical methodology, it is possible to quantify this statistical uncertainty. NRI data were collected at more than 800,000 sample sites nationwide. This is a very large sample, which means that the data can be legitimately used to analyze issues at many geographic levels -- national, regional, State, and sub-State (multi-county). However, the NRI was not designed for analyzing issues at the county level.
897-B Harrison Street, S.E.
The NRI polygon feature class component of this data set is comprised of four original source data sets. These include: 1) Major Land Resources Areas of the United States (MLRA) - compiled National Atlas of the United States 2) County Boundaries - compiled by the National Atlas of the United States from 1:2,000,000 USGS DLGs 3) Hydrologic Unit Codes (HUCS8) - produced by the U.S. Geological Survey from 1:250K Hydrologic Unit Maps 4) Federal Lands - compiled by National Atlas of the United States. The STATSGO polygon feature component of this data set was compiled from soils data and soils maps by the U.S. Department of Agriculture, Soil Conservation Service.
Intersected the original source data sets: MLRA, HUCS8, CountyBoundaries, using ArcINFO workstation geoprocessing command, Intersect.
Dissolved original source Federal Lands polygon on FederLand attribute field, using ArcGIS geoprocessing tool, Dissolve.
Unioned the dissolved Federal Lands data set to the intersected HUCS8/MLRA/CountyBoundaries data set, using ArcGIS geoprocessing tool, Union, resulting in the NRI polygon data set.
From the NRI polygon feature class, polygon features from the eastern half of the United States were selected and exported to a new NRI polygon feature class of approximately the eastern half the continental United States. From the NRI polygon feature class of the whole continental United States, the selected polygons were switched and exported to create a new NRI polygon feature class of approximately the western half of the continental United States.
In two processing steps, the eastern and western NRI feature classes were intersected with STATSGO resulting in a 1) NRI/STATSGO intersected feature class of approximately the eastern United States, and a 2) NRI/STATSGO intersected feature class of approximately the western United States. This was accomplished using the ArcMap geoprocessing tool, Intersect.
The eastern and western NRI/STATSGO intersected polygons were compiled into one geodatabase using the ArcGIS geoprocessing tool, Append, resulting in a single file of NRI/STATSGO intersected polygons for the continental United States.
Metadata created.
Aggregated data based on the fields, FIPSMLRAHUC, MUID, FederalLands, using the Geoprocessing Tool, DISSOLVE, in order to reduce duplicate data.
Dataset copied.
Metadata imported.
Metadata imported.
Internal feature number.
ESRI
Feature geometry.
ESRI
The 5 digit FIPS code of the county or county equivalent.
National Atlas of the United States
Length of feature in internal units.
ESRI
Area of feature in internal units squared.
ESRI
Major Land Resources Area Identification Code
National Atlas of the United States
Code for Federal Lands: Those land areas over 640 acres identified as being administered by the United States Federal Goverment.
National Atlas of the United States
Concatenated Code of FIPS, MLRA and, HUC codes
Waterborne Environmental, Incorporated
STATSGO Map Unit Identification Number
STATSGO
Natural Resource Inventory Polygon Identification - Key for linking to NRI Tabular data
8 digit Hydrologic Unit Code (HUC 8)
USGS
1500 Research Parkway, Suite B223
None
Data can be downloaded from www.geostac.org with a registered user ID and password provided by the Spatial Sciences Laboratory
897-B Harrison Street, S.E.