LARGE SCALE COLOR INFRARED PHOTOGRAPHY PROVIDES GROUND 
TRUTH FOR LANDSAT IMAGERY IN THE PACIFIC NORTHWEST 
by 
John F. Wear 
Eugene E. Wheeler 
State and Private Forestry, U.S. Forest Service 
Portland, Oregon 
ABSTRACT 
The potentials of using LANDSAT computer tapes for land classifica- 
tion and inventory systems in the Pacific Northwest are greatly enhanced 
by interfacing large-scale color infrared (CIR) photography as a primary 
source of "ground-truth." Observations of various types of surface re- 
sources from the ground are generally limited to a short distance which 
provides neither a comprehensive nor sufficiently accurate overview to 
establish an average signature for a LANDSAT pixel of 1.1 acres. Varia- 
tions in distribution on vegetative resources, even on a l.l-acre basis, 
are quite difficult to delineate from a ground perspective compared with 
large-scale photographic overviews ranging from 1:3,000 to 1:8,000 scale. 
Identifying and delineating vegetation and soil types, water re- 
gimes, and a wide spectrum of vegetative conditions and stress factors 
can be implemented with this type of large-scale imagery. The rationale 
for applying this new system to LANDSAT classification of alphanumeric 
computer elements and the aerial photographic procedures required for 
agricultural, range, and forest resources are described in this paper.