increased cost of image acquisition, it becomes mandatory that inter- 
preter training include the application of the major film and film/ 
filter combinations and not remain, as at present, centered on pan- 
chromatic photography. 
  
The image characteristics of most terrain features or patterns 
will vary greatly from one film type to another. If not familiar with 
the particular film type available, the interpreter is often required 
to proceed through a series of thought processes that translate the 
image pattern characteristics of the terrain feature detected on the 
unfamiliar film type to the response characteristics of the film type 
used in training. 
It would seem plausible then, that an inventory of aerial photo- 
graphs would be beneficial to the training of image interpreters. 
Most training courses begin with a need for examples of cartographic 
photography in order that the student gains competency in the rudiments 
of photogrammetry, e.g., scale determination, vertical and horizontal 
measurements, etc. Later in the training course, when instruction is 
provided in the detection and identification of such terrain features 
as soil type, species of vegetation, and drainage channels, the inven- 
tory will again be called upon to provide aerial photographic examples 
of these terrain features. Historically, these examples have always 
been provided on panchromatic film because of the low cost and avail- 
ability. Ideally, however, these examples should include the four 
major film, film/filter combinations employed today, i.e., color, color 
infrared, panchromatic, and black and white infrared. To be effective 
as training aids, these examples should have been acquired within the 
same period of time. Variations in soil moisture, biomass water con- 
tent, and sun angle are only a few of the many variables that can 
effect the image characteristics, if there is a time lapse between 
photographs. 
Equipment 
The equipment required to obtain and utilize multispectral aerial 
photography consists of (1) a camera, and (2) an additive color 
viewer. Both aerial cameras and viewers can be acquired on the com- 
mercial market and are also available through lease or contract with 
a number of aerial photo corporations. 3 
Aerial Cameras: In general, multiband aerial gamera systems are 
either built-up of four or more single cameras" or consist of a 
  
  
2 T. Marlar, and J. Rinker, "A Small Four-Camera System for Multi- 
Emulsion Studies," Photogrammetric Engineering, Vol. 33, No. 11, 
November 1967, pp 1252-1257. 
wl