The distribution of the errors was as follows: - 
+ 
80% of points 0. 0 ft. to * 0.1 15. ( * 0.03m) 
i$ 
18% of points 0.1 ft. (¥0. 03m) to 
0.2 ft. ( 0. 06m) 
1+ 
2% of points 0.2 ft. (f0. 06m) to * 0.3 ft. ( f0. 09m) 
These accuracies were achieved in a typical production project employing standard 
procedures. These results are, therefore, indicative of the degree of accuracy 
which can be expected in practical applications with the Wild A-8. With it, the amount 
of required ground control is reduced, and the overall economy of the photogrammetric 
approach is increased. 
In evaluations based on many large projects, we find Wild A-8 
Autograph an excellent and economical instrument for large scale engineering map- 
ping. Combined with the EK-3 Co-ordinate Printer and the Profiloscope, it provides 
an efficient system for determination of cross section profiles, in highway and railway 
work. It is also useful in triangulation of short strips and other engineering applica- 
tions of numerical photogrammetry. 
An integrated system of photogrammetry and electronic computa- 
tions furnishes the data required by the design and the construction engineer in 
numerical form. In theory, it eliminates the drawing of cross sections. However, 
from a practical point of view, it is necessary that the cross sections and profiles 
be presented in a graphical form so that they can be easily examined by the engineer 
and the contractor. Therefore, the inclusion of an automatic line plotter in the 
integrated mapping system is essential. 
The advantages of employing photogrammetry and electronic com- 
putations in highway and railway engineering are: - 
l. the aerial photography provides a rapid and indisputable record of the undisturbed 
ground and of the progress of construction. 
2. cross section profiles and the earth work quantities are determined by a third 
and impartial party. 
3. difficult terrain does not influence the accuracy of photogrammetric surveys, 
nor materially slow their progress. 
4. the cross sections obtained photogrammetrically reflect the shape of the ground 
more accurately than the cross sections surveyed on the ground. This is par- 
ticularly true in areas of large cuts, where the survey cross sections on the 
ground are often incomplete. 
5. the possibility of human error is greatly reduced since the cross section data 
obtained in the stereoplotting instrument are punched on a tape, the computations 
are performed electronically and the cross sections area drawn automatically. 
6. the photographs obtained at different stages of construction are of great assist- 
ance in observing erosion and drainage problems and will aid in anticipating 
future maintenance problems. 
7. integrated photogrammetric surveys provide a flexible tool which meets the 
fluctuating volume of surveys and avoids costly delays in construction progress.