cedures may
ial film/filter
lon, since the
:dictable dif-
n/filter com-
:e into detec-
South Pacific
a prescribed
zone, while
fferent tech-
tation.
varies little
iterpretation.
ypes of pho-
ot” principle
t coasts and
desirable by
| conditions.
n photo to
ng roads or
on oblique
ited States,
e millimeter
ous photo-
es a simple
distance on
> is known.
quals 8 feet
(691)
on the ground. When an average of ten or twenty measurements must be
rapidly made on each print of a coastal sortie, the value of a “direct reading”
scale is obvious.
The monocular folding or tubular magnifier found in American military
photographic interpreter’s kits, is fitted with a transparent plastic diaphragm,
inscribed with a portion of a 0.001-ft. scale and mounted in position under the
lens so that small objects can be rapidly and accurately measured while being
viewed under the magnifier.
Certain additional equipment being contemplated or developed for pos-
sible use in amphibious interpretation is still under security classification. Such
developments consist mostly of special items designed as solutions to one par-
ticular type of problem and not as replacements for the standard items. Im-
proved models of nearly all the standard items are also under development.
VI. Desired Improvements in Equipment or Techniques.
Consideration of desirable improvements in equipment or techniques in-
fringes necessarily on security classifications given certain projects now in pro-
gress. Where security considerations are involved, neither current project nor
the requirements for the future can be discussed in detail here. Some broad,
general requirements may be noted, however:
1. Better methods of depth determination from aerial photography. World
War II methods are severely limited as to the conditions under which they
may be used. Further, these methods have not proved themselves economically
usable for peacetime underwater mapping. Methods which are economical, reli-
able, and accurate under all conditions are urgently required.
2. Accurate methods of predicting gradients and materials on the beach
above the waterline. Comparatively slight variations in slope and composition
of this unconsolidated medium may make considerable differences in the ability
of vehicles to operate.
3. A reliable system of trafficability prediction. This includes the develop-
ment of suitable symbols or units in which trafficability can be expressed on
maps of mosaics, the development of techniques for determining trafficability
from the photo image, and the creation of suitable keys to enable the average
military interpreter to render trafficability predictions.
VII. Desirable Photographic Film, Filter, and Scale Combinations.
Each photographic interpreter develops his own preferences for photo
scale and quality. These are normally the result of his own area of experience,
and may differ somewhat from the ideas of an equally well qualified analyst
with a slightly different background.
The whole field of optimum image size and quality for various fields of
interpretation has been insufficiently investigated. Not only are the desirable
scales and film/filter combinations unknown, but we have not yet determined
just what in the way of basic image characteristics is required for the inter-
preter to identify objects on photographs. Fundamental research being perform-
ed by Dr. D. MacDonald of Boston University (6) and others may provide a
foundation upon which conclusions in this field may be reached.
The degree of detail available for interpretation is directly proportional to