and 
Sn = 61} 50 +... 8. (15) 
we obtain 
DE (16) 
i.e. the correction v1 of the first strip is the arithmetic mean of the individual first partial sums of the 
junction differences, or the nth part of the last term of the second summation series. If the bows of 
the strips are accidental, this procedure yields good results. Systematical errors, however, cannot be 
eliminated therewith. For this purpose one or two additional control points located somewhere in the 
interior of the block are required, depending on the fact whether or not the systematic errors can be 
reached by a function of the 2nd or of the 5rd degree. Of course this procedure is not restricted to one 
section of the strip, e. g. in the middle, but applicable to as many sections as required. Similar formulae 
may be applied to the adjustment of Ax and Am. In this case the errors are considered as longitudinal 
deviations and not as transversal ones. 
In level adjustment the conditions are different, because the errors in border junctions of successive 
models include, beside the elevation z, the changes of lateral tilt « also. Again we have n —1 con- 
dition equations, but 2n unknowns. Therefore the condition [pp] = min does not result in an un- 
equivocal equation system of n equations with n unknowns, as this is the case with the adjustment 
of y and x. 
The solution of the equation system shows that it is easy to take the mean of the elevations at the-border 
junctions of successive models, and that the lower as well as the upper borders of the block are not 
subject to correction, Thus the bridging differences at the borders of the strips are eliminated by ad- 
justment, The result, however, still differs considerably from the true elevations. 
The equation system immediately becomes unequivocal, if with the individual flight strips the lateral 
tilt @ or the flight altitude z is known or assumed to be free of errors. By our experience w varies 
more than z within one strip. For this reason it is recommendable that the course of the w-tilt be 
investigated, since so far only a few results are available. 
At any rate, level adjustment only based upon control points, located at the corners of the block, and 
upon the bridging of adjacent strips, furnishes unsatisfactory results. Unless the number of condition 
equations essentially exceeds the number of unknowns, i.e. unless a redundancy of determinations is 
available, the adjustment only results in values free of discrepancies, but not in correct, 
especially not in true values. 
Details of the present study will be published in a future publication of the German Geodetic Commission, 
Series A, No.35 (Mitteilung No. 36 des Instituts für Angeroandte Geodäsie). 
  
    
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