by the single interpreters j = 1, 2, 3 ••• m can be considered as 
subset of a basic set E , and we obtain according to ( 3 ) 
k=l 
interpretation result 
obtained by the different 
technical sciences k = 1 , 2 , 3 • •• n 
referred to a certain region. 
The union of the interpretation results e^ is corresponding to ( 6 ) 
possible according to 
n 
(E) = e. e_ e^ o 
'23 
k =1 
kj e 
n 
( 11 ) 
here, however, the sequence of the terras on the right hand side of th 
equation must be observed. It is, e.g., possible that the socio-eco 
nomic interpretation data obtained by a geographer only are of small 
use or of no use at all for the solution of a geological interpreta 
tion problem. The conversion of the sequence can, however, change 
this ratio considerably. 
As is well known, for k = n exists n! permutations. But for theo 
retical considerations and practical experiences only some sequences 
of these permutations can be used in practice. In general, one will 
take into account, in establishing the sequence of interpretation, 
the following items: 
the most evident characteristics shown on the photograph to be 
interpreted or 
the points of viev; considering the interrelations of the technical 
sciences or 
a combination of both these possibilities. 
But evidently, the determination of a sequence of interpretation 
depends primarily on 
the objective of interpretation. 
This objective seems to be decisive, too, for the number k of the 
technical sciences to collaborate. In order to be able to take these 
points of view into consideration, we choose a transitive order so 
that ( 11 ) goes over into 
(E) = Sl ^ e 2 ^ e_ w ... w e n ( 12 ) 
k =1 
which means e^ < e^ = "before 11 e^, etc. 
If within one technical science k* several interpreters collab 
orate in the solution, then the interpretation results e_. obtained