10
of 2:1 on stable base material. The .plotted intersections were
measured on the coordinatograph of a Wild A-7 which was assumed to
have a radial standard error of 10ji.
A conformal adjustment of the measured data to the calibrated grid
data was made with a unit radial standard error of 15m at original grid
scale. This standard error has been corrected for the effects of in
accuracy of the Wild A-7 coordinatograph and it reflects the total
combination of errors of the carriages plus the plotting table mechanism.
8.3 Model Flatness Tests
Model flatness tests were conducted with 9" x 9" Wild grid plates
scribed with-15m. line weight lines. Model parameters were:
focal length = 150 mm
forward lap = 60°/ o
Exposure Station elevation
above datum ~ 150 mm
Observations were made in the model at 15 mm intervals and recorded
at the console. The following unit standard errors were obtained in
plan and elevation after conformal adjustment to the known calibrated
coordinates of a theoretically flat model.
Up = 6Am (radial standard error)
°h = 9-9m
These results reflect a precision C factor of C « k600.
9• Constants Tests
These series of tests were to determine the numerical computation
accuracy of each of the correction functions as computed in the DDA
computer. Each test was performed using the previously mentioned
calibrated Wild Plates in each of the ate carriages. Machine coordi
nates read from the console were compared against theoretically com
puted coordinates to determine accuracy of compensation. Summary
results of the tests performed are shown in Table I.
Tests Wo. 1 and k were conducted on the basis of single 9" x 9"
format.
Tests Wo. 2 and 3 were conducted assuming a stereo model having
the following characteristics: