5. In general, when choosing 0. = 0 = 10u as a priori standard 
deviation for all tie-points and’c,=2 in the linear choice function 
as shown in formula 3.1 an error of 30 cm in one of the control 
coordinates can be traced «easily. 
However, when decreasing O and O_ to 54 the impact on the boundary 
values of the control points is significant (see table 6). 
Comparing the eigen value results of experiments 5 and 6 the same 
effect is clearly shown. 
The overall conclusion may be that if the control points are spread 
out along the periphery of the block the impact of those points on 
the final result of the block adjustment in terms of reliability and 
precision is significant. However, it is also clear that if it is 
possible to decrease the a priori standard deviation of the model co- 
ordinates, the final result becomes rapidly better. 
REFERENCES 
/1/ Baarda, W.: A testing procedure for use in geodetic networks. 
. Netherlands geodetic commission, Delft. 1968. 
/2/] Baarda, W.: S-transformations and criterion matrices, 
Netherlands geodetic commission, Delft. 1973. 
/3/ De Heus, H.M.: Precision in case of combined point determination. 
Paper presented at ISPRS commission III symposium 
Rovaniemi 1986. 
/4/ Van Mierlo, J.: S-transformations. internal report Delft University 
of Technology, department of geodesy. 
/5/ Molenaar, M.:. The connection of aerotriangulation blocks re- 
. considered. Paper presented at ISPRS congress, 
Rio de Janeiro. 1984. 
/6/ Molenaar, M., Karandis, D., Bouloucos, T.: A substitute matrix for 
photogrammetrically determined point field. Paper 
presented at ISPRS congress, Rio de Janeiro. 
/7/ Molenaar, R.C.: The inertial reliability in a 3-Dimensional strip 
adjustment with independent models. Paper 
. presented at ISPRS congress Hamburg. 1980. 
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