indirect manpower requirements for materials preparation, aerial 
triangulation, coordinate plotting, and other support, would 
be variable according to the structure and production requirements 
of the organization. Direct manpower requirements, i.e., the 
manpower requirement for operation of the instrument, is one operator 
for each instrument. There is some evidence that, under certain 
conditions, this requirement may be reduced to two operators for 
three instruments. 
53. Tests Results: The available test data for the B-8 Stereomat 
were obtained by the Army Map Service (AMS) using the prototype 
instrument. Results of these tests are as follows: 
a. Grid model flatness tests were performed with the 
instrument in both the automatic and conventional plotter modes. 
Precision grids were used from the stereo grid model, with a base/ 
height ratio of 0.6, at two projection distances, 262 and 3llmm. 
The instrument elevation of 23 grid intersections, in the standard 
pattern, was read manually (by the operator) and automatically. 
Three orientations were made of the grid model. The average of 
the standard deviation (g) of the 23 points from a true plane 
was found to be 1/7585 of the projection distance for the points 
read by the operator. The automatic mode provided a g of 
1/10,032 of the projection distance. 
b. Terrain model flatness tests were conducted with the 
instrument in both the automatic and conventional modes. The test 
model was absolutely oriented to five control points. The instrument 
elevation for 50 points of known elevation was read manually (by 
the operator) and automatically. Three separate orientations of the 
model and three sets of readings were made. The average g for 
the three models read manually was 1/4946 of the flight altitude. 
c. The averageg for the automatic reading of the three 
models was 1/5648 of the flight altitude. These test data are 
equivalent to a "C" factor of 1700 of the instrument in the automatic 
mode. 
d. From previous experience with instrument evaluations, 
the equivalent "C" factor determined from model flatness tests 
must be reduced by a factor of 1.5 to provide a more reliable 
estimate of contouring accuracy. Thus, a '"C" factor of 1100 can 
be predicted for the Stereomat B-8. This is considered to be 
approximately that which can be expected from the B-8 Aviograph. 
Therefore, it can be concluded that, in a static mode, the Stereomat 
System does not deteriorate in any way from the accuracy of the 
basic instrumentation. 
e. However, when the accuracy of the instrument was tested 
in the dynamic automatic contouring mode, the ''C" factor was reduced 
by a factor of 3. These estimates of contouring accuracy were made 
on the unedited (or rough) contours produced by the instrument. 
Because of the inertia and other characteristics of the scanning 
system in the automatic contouring mode, the Stereomat tends to 
erroneously position contour turnarounds on ridges and streams. 
A topographer, who is familiar with these characteristics, can 
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