27. 
computations were made on a different computer using a computational method 
based on a fundamentally different formulation. Consequently, the two 
methods are not comparable in all respects. An absolute comparison would 
be possible only if the same computer and the same general procedure were 
used to perform two extensions in which: (a) the stereopair was used as 
the basic unit; and (b) the triplet was used as the basic unit. In spite 
of the dissimilarity, it is felt that this comparison shows the superiority 
of the triplet over the stereopair. 
The primary advantages of analytical aerotriangulation as developed in 
this investigation are: (l) the reduction in error propagation in analytical 
cantilever extensions and bridges which results from use of the triplet as 
the basic unit; and (2) the characteristics of the least squares adjustment 
which allows a statistically meaningful evaluation of the quality of each 
triplet and also permits elimination of points in which measurement errors 
exceed a pre-selected rejection criteria. On the basis of tests using 
fictitious data containing random errors, use of the triplet as a basic unit 
is feasible. Further tests should be performed with actual photographic 
data before any attempt is made to evaluate use of the triplet for practical 
mapping problems.