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: