<logic>Certain
node/geometry and topology GT- polygon/chain relationships are
collected or generated to satisfy topological requirements (the GT-polygon
corresponds to the soil delineation). Some of these requirements
include: chains must begin and end at nodes, chains must connect to
each other at nodes, chains do not extend through nodes, left and
right GT-polygons are defined for each chain element and are
consistent throughout, and the chains representing the limits of the
file (neatline) are free of gaps. The tests of logical consistency
are performed using vendor software. The neatline is generated by
connecting the explicitly entered four corners of the digital file.
All data outside the enclosed region are ignored and all data
crossing these geographically straight lines are clipped at the
neatline. Data within a specified tolerance of the neatline are
snapped to the neatline. Neatline straightening aligns the digitized
edges of the digital data with the generated neatline (i.e., with
the longitude/latitude lines in geographic coordinates). All
internal polygons are tested for closure with vendor software and
are checked on hard copy plots. All data are checked for common soil
lines (i.e., adjacent polygons with the same label). Quadrangles are
edge matched within the soil survey area and edge locations
generally do not deviate from centerline to centerline by more than
0.01 inch. Quadrangles in this soil survey are not edge matched to
those in the Rutherford County, Tennessee, soil survey.</logic>
<complete>A
map unit is a collection of areas defined and named the same in
terms of their soil and/or nonsoil areas. Each map unit differs in
some respect from all others in a survey area and is uniquely
identified. Each individual area is a delineation. Each map unit
consists of one or more components. Soil scientists identify small
areas of soils or miscellaneous (nonsoil) areas that have properties
and behavior significantly different than the named soils in the
surrounding map unit. These minor components may be indicated as
special features. If they have a minimal effect on use and
management, or could not be precisely located, they may not be
indicated on the map. Specific National Cooperative Soil Survey
standards and procedures were used in the classification of soils,
design and name of map units, and location of special soil features.
These standards are outlined in Agricultural Handbook 18, Soil
Survey Manual, 1993, USDA, SCS; Agricultural Handbook 436, Soil
Taxonomy, Soil Survey Staff, 1975, USDA, SCS; and all Amendments;
Keys to Soil Taxonomy, Soil Survey Staff, (current issue); National
Soil Survey Handbook, title 430-VI, (current issue). The actual
composition and interpretive purity of the map unit delineations
were based on data collected by scientists during the course of
preparing the soil maps. Adherence to National Cooperative Soil
Survey standards and procedures is based on peer review, quality
control, and quality assurance. Quality control is outlined in the
memorandum of understanding for the soil survey area and in
documents that reside with the Natural Resources Conservation
Service state soil scientist. Four kinds of map units are used in
soil surveys: consociations, complexes, associations, and
undifferentiated groups. Consociations - Consociations are named for
the dominant soil. In a consociation, delineated areas are dominated
by a single soil taxon and similar soils. At least one half of the
pedons in each delineation are of the same soil component so similar
to the named soil that major interpretations are not affected
significantly. The total amount of dissimilar inclusions of other
components in a map unit generally does not exceed about 15 percent
if limiting and 25 percent if nonlimiting. A single component of a
dissimilar limiting inclusion generally does not exceed 10 percent
if very contrasting. Complexes and associations - Complexes and
associations are named for two or more dissimilar components with
the dominant component listed first. They occur in a regularly
repeating pattern. The major components of a complex cannot be
mapped separately at a scale of about 1:24,000. The major components
of an association can be separated at a scale of about 1:24,000. In
each delineation of either a complex or an association, each major
component is normally present, though their proportions may vary
appreciably from one delineation to another. The total amount of
inclusions in a map unit that are dissimilar to any of the major
components does not exceed 15 percent if limiting and 25 percent if
nonlimiting. A single kind of dissimilar limiting inclusion usually
does not exceed 10 percent. Undifferentiated groups -
Undifferentiated groups consist of two or more components that do
not always occur together in the same delineation, but are included
in the same named map unit because use and management are the same
or similar for common uses. Every delineation has at least one of
the major components and some may have all of them. The same
principles regarding proportion of inclusions apply to
undifferentiated groups as to consociations. Minimum documentation
consists of three complete soil profile descriptions that are
collected for each soil added to the legend, one additional per
3,000 acres mapped; three 10 observation transects for each map
unit, one additional 10 point transect per 3,000 acres. A defined
standard or level of confidence in the interpretive purity of the
map unit delineations is attained by adjusting the kind and
intensity of field investigations. Field investigations and data
collection are carried out in sufficient detail to name map units
and to identify accurately and consistently areas of about 5 acres.</complete>