Logical_Consistency_Report:
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.
The quadrangles in this soil survey are edge matched to quadrangles
in the Bedford County, Pennsylvania, Franklin County, Pennsylvania,
and the Washington County, Maryland soil surveys. Most feature edges
and descriptive attributes are matched between this survey and the
Bedford County and Franklin County, Pennsylvania soil survey. The
survey area boundaries match.
Completeness_Report:
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.