REPORT OF COMMISSION VII 
GVII-65 
e. Outline the storage units of finished products by interpreting along 
transportation lines going out of each factory. 
f. Designate the general direction of flow of processing from raw material 
units to finished product units in each factory. 
Scales larger than 1/10,000 
g. Outline the various kinds of internal transportation lines (e.g., railroad, 
pipeline, electric line). 
h. Identify specific raw materials. 
j. Identify specific power and heat units and distribution lines of power 
and heat. 
k. Identify specific finished products. 
l. Outline specific flow of processing from raw materials to finished prod 
ucts. 
m. Identify specific stage of processing in individual buildings. 
n. Identify industry associated with each main factory (e.g., shipbuilding 
with steel fabrication, chemical production with petroleum refining. 
MILITARY FEATURES 
Military features need to be recognized as such to prevent loss of time dur 
ing peace-time interpretation of defense areas or with war-time photography. 
Often military activity is characterized by light tones of disturbed soil in pat 
terned or patternless lines and spots, the obvious abnormal patterns of camou 
flage, or the presence of bombs or bomb bursts on the coverage. Such features 
need be observed only long enough to establish their military classification and 
lack of significance to most peace-time objectives of interpretation. If, however, 
photography is being analyzed for military purposes, the procedures for identifi 
cation need to be prepared on the bases of kinds of weapons, vehicles, and de 
fensive or offensive operations involved in the area of coverage. 
Air Photo Interpretation Keys 
An air photo interpretation key is a systematic listing of the observable 
distinguishing characteristics of an element of a landscape. In general, such a 
key is prepared to make possible the rapid recognition of a feature photographed. 
The key is procedural if it is used by a selective process that progresses from 
alternative general characteristics to alternative specific ones (such as, dendro- 
logical classifications in forestry by dichotomous listings). However, such aids 
to procedure are limited in number and availability. 
It is unlikely that the future of air photo interpretation procedures depends 
on the production of more interpretation keys. In fact, keys may have been 
overemphasized already. Furthermore, keys have limitations. To use many of 
those available requires far more than average knowledge of the content of a 
field of study, making the key of primary value to only its inventor. Standardi 
zation of key forms is difficult because various analyses require different and 
variously arranged facts. Terms like photographic texture are difficult to sub 
divide for detailed description. Also, keys often are useful only for specific 
photography. For example, a vegetated area may vary greatly in photographic 
tone, texture, and stereoscopic appearance with changes in scale, photographic 
time (diurnal and seasonal), shadows on the photos, and photographic quality 
(exposure, development, resolution, and lens quality). Or, the same cultural 
feature may appear quite differently in two areas because of cultural differences 
of the people concerned.