Vegetation Classification and Mapping Project Report - USGS

Base Map Class Development
overlays, was then added to the attribute
table of each base map polygon.
Additional attributes, including vegetation
associations and communities, were
then incorporated using a tabular join in
ArcGIS 9.2. The resulting vegetation map,
in shapefile format, was then reviewed
independently for attribute accuracy
through a “heads-up” comparison of
the vegetation map with the original
orthorectified overlays in the ArcMap
application of ArcGIS 9.2.
3.2 Results
The vegetation map database for PEFO
(fig. 9, table 7) encompasses 46 base map
classes:
● 8 classes describing infrastructure
● 5 describing land cover and geology
types
● 4 describing sparse vegetation
● 15 describing grasslands
● 15 describing shrublands
● 2 describing woodlands and forests.
The vegetation map database is
georeferenced to Universal Transverse
Mercator (UTM) projection North
American Datum of 1983 (NAD 83) zone
12.
The vegetation map database contains
6,989 polygons, of which 1,956 (28%) are
smaller than 0.5 ha (table 8). The majority
of the vegetated polygons smaller than
0.5 ha in size occur in nine base map
classes. Map classes that occurred in the
barren badlands were relatively easy to
distinquish from unvegetated areas on
the aerial photography and were often
mapped even when the patches were less
than 0.5 ha in size.
but were included within the surrounding
mapped vegetatation: 1) Artemisia filifolia
/ Bouteloua eriopoda Shrubland, 2)
Forestiera pubescens Temporarily Flooded
Shrubland Alliance, 3) Krascheninnikovia
lanata Dwarf-shrubland, 4) Suaeda
moquinii Shrubland, 5) Sporobolus
coromandelianus Herbaceous Vegetation,
and 6) Sporobolus cryptandrus Great
Basin Herbaceous Vegetation. These
plant communities frequently occurred
in patches smaller than the minimum
map unit and are not characteristic of
any of the base map units. Pinus edulis
– (Juniperus osteosperma) / Bouteloua
gracilis Woodland was also not mapped as
a unique map unit but was incorporated
with One-seed Juniper / Bigelow’s
Sagebrush Shrubland as a base map class.
A summary of the base-map class
distribution, as well as the distribution of
the management, group, and macrogroup
map classes, is presented in section 4. A
key to the base map classes, crosswalked
to plant community, as well as the group,
macrogroup, and management map
classes, is presented in Appendix E.
Appendix F lists the relationship of plant
communities defined in section 2 to base
map classes and to the other three map
schemas. Photosignatures and summaries
of the characteristics of each base map
class are presented in Appendix G.
All base map classes have a one-to-one
representation with a plant community.
Six plant communities were not
specifically mapped, as they could not be
distinquished on the aerial photography,
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