68 REPORT OF COMMISSION VII 
sembly and erection to the launching, fitting out and completion. Even repairing 
and overhauling work can be kept under observation. It is even possible, through 
measuring the position of the keel blocks in dry and floating docks, to establish 
the kind of ships for which the docking preparations are intended. 
Intelligence valuable from a marine operative point of view, however, may 
also be obtained from ground reconnaissance photos taken at a great distance 
from ships or positions ashore of naval forces, convoys or single vessels. 
  
Fic. 10. A vertical of an airfield reproduced as an annotated photo showing: (1) Hangars, 
(2) Open aircraft emplacements, (3) Road for moving aircraft, (4) Aircraft type FW 190, (5) Air- 
craft type Ju 88, (6) Aircraft type He 111?, (7) Aircraft type Ju 86 in emplacements, (8) Anti- 
aircraft tower, (9) Shelter (zig-zag line), (10) Shelter (pit), (11) Stores or workshop premises (rails 
laid for the transport of heavy material), (12) Rails, (13) A.A. 
The most important and usually the most arduous task, when interpreting 
such long distance photos, as well as aerial photos of marine targets, is identify- 
ing the different types of ships, their classes and units. The difficulty is that the 
scale of the photograph is often considerably smaller than that normally neces- 
sary in order to be able to analyze the details of the vessels. 
A further example of strategic photo-interpretation is, through making 
comparisons and taking measurements in reconnaissance photos of target areas, 
to establish the effect of strategic air raids carried out. 
TACTICAL APPLICATION 
Through detail analysis of newly taken reconnaissance photos within the