value 
2.1) 
soid 
with 
)Var- 
root 
the 
pro- 
each 
This is the second criterion used. 
In terms of variances this criterion means: 
H G H 
mia UE Sp Cual ax OFF 
Note: The general eigen value problem is invariant with respect to a 
non-singular transformation. In view of the fact that the comparison , 
of the two matrices should be made after a transformation to the 
same S-base, it is obvious that the choice of the S-base is not 
important for the comparison. 
3. EXPERIMENTS 
A series of experiments have been carried out with simulated plani- 
metric model blocks [8]. 
For each experiment the covariance matrix of the point field is 
produced through the adjustment algorithm. 
Also a substitute matrix for the point field is generated. 
The two matrices are transformed into the same S-base, and compared 
using the results of the general eigen value problem. 
The parameter values of the choice functions which generate the best 
substitute matrix, according to the criteria formed in paragraph 2, 
were obtained by successive trials. 
The following block configurations with the indicated control dis- 
tributions were treated: 
A1: A2: A3: 
mr ff 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
B1: „32: 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
C1: C2: A 
; | Azcontrol point 
  
  
  
  
  
  
  
  
  
  
  
  
Figure 2 
For each model of the above blocks the following cases were consi- 
dered. 
. four single tie points (^ corners) 
». four double tie points 
. six single tie points (6 standard positions) 
e Six double tie points