Abstract:
In March 2005 the Oregon State University Herbarium launched its new, free online Oregon
Vascular Plant Atlas for public use. This Atlas allows users to access location information
from over 385,000 vascular plant specimen and observation records in the state of Oregon.
The potential applications of such spatial information are almost limitless; users can examine
the spatial relationships between plants and a variety of environmental variables within plant
communities (soils, precipitation, elevation etc.). The maintenance and accuracy of this
database is therefore critically important in order to provide the highest quality information
to Atlas users. Several projects were identified to increase the accuracy and precision of the
Plant Atlas spatial data including: (1) correction of points with mismatched township/range
and county information, (2) comparison of Oregon State University (OSU) Herbarium and
Oregon Natural Heritage Information Center (ORNHIC) georeferencing results, (3) creation
of quarter section and quarter-quarter section location names, and (4) analysis of elevation
information using digital elevation models. These projects were completed using geographic
information system (GIS) software, as well as Microsoft Access data management software.
New location names, or LocNames, were created for township/ranges bisected by county
lines, increasing the accuracy of the referenced location. LocNames were also created for
specimens with quarter section and quarter-quarter section information. These combined
projects resulted in the creation of 1,876,587 new location names. Analysis of the ORNHIC
and OSU Herbarium georeferencing results showed the majority of points were similarly
georeferenced, however, one-third had some quality issue. Finally, the quality of the
elevation information stored in the Vascular Plant Atlas database was shown to include
potential data entry conflicts between meters and feet, as well as potential georeferencing
problems. The results of these projects will help increase the accuracy of georeferenced
specimen locations, as well as provide important information to help herbarium staff identify
areas of needed quality control.
