2. 
the limitation of stereo-vision imposed by physical and instrumental 
characteristics (two eyes and two projectors), no longer exist. Figuratively 
speaking, the mathematical model may be observed in triplicate and the assembled 
units contain 100$ overlap in one common photograph. Mathematical observation 
of three photographs simultaneously permits detection of large plate coordinate 
errors since residuals are available for both x and y plate coordinates. 
Presence of 100$ overlap between the one common photograph in successive 
basic units permits more reliable unit assembly and reduces the propagation 
of error through the strip. Use of this theory, coupled with the simplifications 
introduced by performing relative orientation, unit assembly, and transformation 
to ground control in successive steps, provides additional accuracy with 
maximum computational efficiency. 
The feasibility and advantages of employing the triplet as a basic 
unit for analytic aerotriangulation weie studied at Cornell University. A 
complete triangulation procedure was developed for the electronic computer 
to permit testing of the method using the three following major classifications 
of data: (l) fictitious data which was theoretically correct; (2) fictitious 
data in which rendomly distributed displacements were applied to plate 
coordinates; and (3) actual photographic data. Results from these tests 
provide an evaluation of computational accuracy on both fictitious and real 
photography.