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detail concerning any given feature, as can the observer who stands beside it
on the ground.
In the nearshore area, aerial photography can, under proper conditions,
estimate water depths and identify and locate rocks and shoals. But a trained
swimmer with proper equipment can determine the water depth at several
points with complete accuracy and can bring back actual samples of the sand
bottom or underwater rock outcrops.
On and behind the beach itself, a ground observer can determine in great
detail type of material and particle size, can measure gradients, and can esti-
mate trafficability characteristics for several spots as time permits. While. the
photographic interpreter is not limited in how many spots he can examine he
can never provide the amount of detail on any of them as can be produced by
a trained observer on the ground.
An incident which occurred during the Normandy invasion planning period
illustrates the relationship between ground and air-photo intelligence. Some
weeks before the invasion a small-boat night-reconnaissance mission was con-
ducted in the Omaha Beach Area. Personnel on this mission (all experienced
observers) fixed their position as best they could by means of bearings on local
landmarks and took several sets of soundings and bottom samples in the near-
shore area. The soundings they reported, when plotted, did not check at all
with previous (and admittedly less precise) depths obtained from photography.
Had the difference been slight, Naval photographic interpreters would have
assumed the boat crew right and the photo depths wrong; but these diver-
gences were so great that more investigation seemed indicated.
A close study of the recorded navigation of the boat was made. This;
together with a careful examination of the coast in vertical aerial photography,
showed that by a simple error in landmark identification, the boat could have
been at another location several thousand yards up the coast when the obser-
vations were made. When the soundings were plotted at this alternate location
they checked almost exactly with depths obtained from photography.
With the position thus corrected, the data gathered by the boatcrew could
be used to correct and amplify photographic intelligence in the offshore area.
IX. Presentation of data.
Coleman discussed the presentation of amphibious data in some detail in
a previous paper (1). Little would be gained by repeating that material here.
However the necessity for graphic presentation cannot be over-emphasized.
A recent Soviet book on military photographic intelligence (6) sets forth
a Russian doctrine, which might be paraphrased roughly as follows:
"Whenever possible, prepare an annotated mosaic or photograph. If time
does not permit, submit an annotated sketch. If you haven't time to make a
sketch, submit a written report."
This is also excellent doctrine for the American photographic interpreter.
In amphibious intelligence particularly, where a requirement exists to present
a great amount of detailed data to a large number of operational personnel only
a short time before the operation, graphics are essential.
Detailed, annotated chart-maps of the landing area, annotated large scale
mosaics of each beach with defense overlays, shoreline sketches for boat cox-
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