Soil Survey Geographic (SSURGO) database for Trempealeau County, Wisconsin

This data set is a digital soil survey and generally is the most
detailed level of soil geographic data developed by the National
Cooperative Soil Survey. The information was prepared by digitizing
maps, by compiling information onto a planimetric correct base
and digitizing, or by revising digitized maps using remotely
sensed and other information.

This data set consists of georeferenced digital map data and
computerized attribute data. The map data are in a soil survey area
extent format and include a detailed, field verified inventory
of soils and miscellaneous areas that normally occur in a repeatable
pattern on the landscape and that can be cartographically shown at
the scale mapped. A special soil features layer (point and line
features) is optional. This layer displays the location of features
too small to delineate at the mapping scale, but they are large
enough and contrasting enough to significantly influence use and
management. The soil map units are linked to attributes in the
National Soil Information System relational database, which gives
the proportionate extent of the component soils and their properties.

SSURGO depicts information about the kinds and distribution of
soils on the landscape. The soil map and data used in the SSURGO
product were prepared by soil scientists as part of the National
Cooperative Soil Survey.

Digital versions of hydrography, cultural features, and other
associated layers that are not part of the SSURGO data set may be
available from the primary organization listed in the Point of
Contact.

The accuracy of these digital data is based upon their
compilation to base maps that meet National Map
Accuracy Standards at a scale of 1 inch equals 1,000
feet. The difference in positional accuracy between the
soil boundaries and special soil features locations in the
field and their digitized map locations is unknown. The
locational accuracy of soil delineations on the ground varies
with the transition between map units.

For example, on long gently sloping landscapes the transition
occurs gradually over many feet. Where landscapes change
abruptly from steep to level, the transition will be very
narrow. Soil delineation boundaries and special soil features
generally were digitized within 0.01 inch of their locations on
the digitizing source. The digital map elements are edge matched
between data sets. The data along each quadrangle edge are
matched against the data for the adjacent quadrangle. Edge
locations generally do not deviate from centerline to centerline
by more than 0.01 inch.