|
Research
Problem and Background:
Remote sensing techniques were investigated for identifying and
mapping the infestations of invasive noxious weeds. The research
targeted purple loosestrife in the Denver area and in central Washington
state, and leafy spurge north of Golden and in the headwaters of
Spring Creek, near Buffalo Creek, Colorado. All areas of research
were sites at which biocontrol insects were released. Aerial photography
recorded initial presence of the weeds and subsequent changes, particularly
in response to the insects.
Project
Objectives:
The project objectives were to:
- Obtain high resolution, stereo aerial photography of the weeds
in the flowering and the autumn leaf seasons for identification
by color and texture
- Investigate possible computer identification techniques of color
recognition for classification of the weeds
- Map the past and present extent of the weeds in a geographic
information system
- Document any changes in the plant infestations resulting from
the biocontrol insects.
Overall
Outcome or Conclusions:
Aerial images on positive
natural color transparency film were obtained for analysis of the
study areas. Many color manipulations were tried in the computer
system but with limited success. It was determined that looking
at the aerial photos in stereo and then transferring their positions
to a geographic information system was best, though labor intensive.
There was too much background speckle and color mixture in the images
for automatic computer processing. The human eye and brain remained
superior for identification and mapping.
The 1998 images showed major insect damage in
the Washington area, which is now being documented. Damage in the
Denver area made the infestations so small that they were becoming
unrecognizable in the aerial images. Leafy spurge changes occurred
after the last aerial images and were documented by close up photos
taken from the ground.
Partners:
U.S. Geological Survey and U.S. Fish and Wildlife Service
Publications
and/or Other Deliverables
Quantifiable images of insect damage to the weeds were obtained
near the end of FY98. Numerous publications are planned for the
near future.
|
