The scale of all photography was 1:10,000 and in tests 1 and 2, observations were made at 
model scales of lix, 2x and ^x the photograph scale. Test 5 was observed at a model scale 
of 24x photoscale and in all three cases, the following control distributions and densities 
were used 
—e 
  
  
$—9—9$—9 
  
  
  
     
  
  
  
| 0—o0 
A B C D E F 
For test 4, only two-thirds of the test area was visible due to bad flying and consequently 
only points 1-21 were observed. The model scale was 23x photoscale and the following 
control combinations were used in the transformations. 
      
A B G 4 5 10:07 E F 
The results of all tests are presented in the following table. 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
A | B | C | D E F 
CONTROL COMBINATIONS 
Model A : 
Scale Standard Deviations - 6x, $y, OD (microns @ photoscale) 
Test 1 15x 161,13 | 201 15 9|18}| 14| 12] 18] 16| 10| 19] 14] 9 161 14] 10]| 18 
©. o X 14 |-12 | 19/14 |} 13 | 19} 13 16| 201 14| 131 19 15] 12| 18] 14] 12] 19 
elled 5X 18] 121221 341 10|: 17] 15] 15] 201 17 ol 19] 1| 1i1| ie] 141. 9| 17 
Test 2 lix 14 | 141 20] 14 | 14 | 20] 16] 15| 20| 15| 10 17] 121 12] 17] 135| 14] 19 
Relative 2 x 15.12 19| 14 | 12| 18) 14/15) 20] 45 | 10 is] 12] 11] 1e] 15| 15) 19 
Orientation 5 x 16|[37]2*] 15116|22] 15| 14| 20] 15| 11, 18 141 15] 19] 141| 15) 21 
| 
Test 3 | | 
Mod.Levelled | 24x 20125 | 33] 21 126] 33]. 20| 25| 32] 19 | 25 20| 20] 251 ^1 14 11.18 
Mod.Levelled | 25x 321301161 12]310] 161 121] 34] 19] 15; 131| 171 12| 11 16 12 10/- 15 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Although the above tests are far from exhaustive (research in this respect is continuing), 
they nonetheless reflect two significant features of single model triangulation, namely that 
planimetric accuracies appear to be insignificantly affected by changes in either the model 
scale or control densities. The effect of false tilts in the adjustment of relatively 
oriented models is being investigated and it is hoped to present results of these tests 
shortly. 
   
Acknowledgement 
The author is grateful to the South African Council for Scientific and Industrial Research for 
providing technical assistance for the above project. Thanks are also due to the Aircraft 
Operating Company for providing the test data and to Mr R.D. Marais who assisted with the 
observing and data processing. 
  
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