vegeta- 
ics on 
ropland 
erage). 
oscopic 
in the 
'ground- 
grouped 
| which 
out 50 
revealed 
lied to 
t pos- 
ls were 
lividual 
»scribed 
indicate 
flight 
proper 
ssifica- 
  
m 739 = 
Individual pixels and pixel groups were actually located on the large- 
scale CIR photos by transfer methods which are now briefly described. 
The first step on the Goose Lake project was to locate the general 
position of the low flight photos on the unsupervised classification of 
the study area. These general areas were then transferred to USGS quad 
sheets and to high elevation U-2 photos. The low flight color IR photos 
were also located on the U-2 photos and USGS quad sheets. The individual 
pixels and pixel groups were then located, described, and clustered into 
management groups. A new classification of all of the plots was then 
made and compared with the low flight CIR photos, and on-the-ground know- 
ledge of the plots. 
DISCUSSION 
Inventory Efficiency 
A large portion of the cost of an inventory project regardless of the 
system is absorbed in the accumulation of "ground-truth." The Goose Lake 
project originally involved 150 ground-truth plots on cropland and range- 
land which varied from 10 to 160 acres. Each of these were visited two 
or more times in the field. Each plot required from 2 to 4 hours per 
trip. 
Use of large-scale CIR photography would have reduced the number of plots 
to about 50 with one trip to each. Thus, the time spent on each plot 
with photos in hand would have been 1 to 2 hours. 
The sequence followed on the Goose Lake project is not considered the 
desired method for ground-truthing, nor vill it be followed on the five- 
county project. 
The revised inventory technique will follow these steps. 
1. An unsupervised classification will be analysed and plots 
selected from the 960,000 acres covered by low flight photography. 
2. Individual pixels and pixel groups of the selected plots will be 
located on the CIR photos and sampled on-the-ground.