PART A: THE 5 Ss
There are five basic factors an IA uses to help in identifying an object, activity, or
installation found on aerial photography. They are size, shape, shadow, shade, and
surroundings (often called the "five Ss").
1. Size. The size of an object (Figure 1-1) can readily aid in its identification and also in
the identification of surrounding objects.
a. If the scale of a vertical photo is known or can be-determined, it is a fairly simple
process to take a measurement and determine the actual size of the object to be
In the analysis of equipment, you should find accurate measurements are a
c. You can also use relative size. Look at Figure 1-1. If you know the object on the
right is a house, by comparing the size of the center object to the known object (the
house), you might determine it is a garage or large storage building. If you have made this
deduction, you might decide the object on the left is a small storage shed or an outhouse.
Figure 1-1. Size.
2. Shape. The shape of an object (Figure 1-2) is a definite aid in your identification
process, because one of the first things you must do is determine whether the object is
natural or manmade.
a. Natural terrain features are irregular in shape, but manmade objects have very
regular geometric patterns with straight lines and regular curves. Using this knowledge,
the IA can quickly scan a series of photographs and eliminate the irrelevant from the
relevant, distinguish cultural features from those of military significance, and devote
attention to the important area.
b. The importance of shape is further emphasized when you realize the enemy's
camouflage efforts are primarily directed toward breaking up the shape of enemy
installations and equipment.