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High overcast conditions result in shadowless photography. The trees and 
shrubs do not cast shadows, thus permitting canopy penetration. Each 
layer of ground cover can be detected and described by utilizing the 
shadowless photography concept. The result is a potential to evaluate 
differences in signatures on plots of similar general appearance. 
3. Time of day 
Time of day is important under all conditions other than high overcast. 
The angle of the sun must be kept at a minimum. The taller the vegeta- 
tion, the more critical the time of day. Timing of photography for the 
Five-County Project was as follows: 
Range and Croplands 
a. March through May, 10:00 a.m. to 3:00 p.m. 
b. June through August, 9:00 a.m. to 4:00 p.m. 
c. September through November, 10:00 a.m. to 3:00 p.m. 
Forestlands 
The above times are reduced for forestry photography by starting 1 hour 
later in the morning and stopping 1 hour earlier in the afternoon. 
4. Elevation 
As previously mentioned, the elevation will usually vary with the size of 
the vegetation. The amount of detail desired will also affect the eleva- 
tion at which plots are flown. The Five-County Project was photographed 
as follows with the 12-inch focal length KA-2. 
a. Cropland - 3,000 feet 
b. Rangeland - 6,000 feet 
€. Forestland - 8,000 feet