38 O.E.E.P.E., Commission B 
Report on the Work Carried out by Commission B of the O.E.E.P.E. 
during the Period of September 1956-August 1960. 
The report on the activity of Commission B presented by Prof. Solaini and Ing. Bel- 
fiore at Stockholm and published in the review “Photogrammetria” ended by giving in- 
formation on the contribution and work systems of the Centres engaged in the work of 
the Commission itself which is interested in the applications of aerial triangulation for 
large and medium scale mapping. 
After the Stockholm Congress the calculation and working-out of the material 
gathered was started under the direction of Ing. Belfiore, who was Chairman of the 
Commission at the time, in order to answer two fundamental questions put by the Com- 
mission, viz.: 
— To establish statistically the accuracy of aerial triangulation of strips for large scales 
— To chose the best method of compensation of aerial triangulations. 
The caleulations adopted were confined to the compensation of (bridging) triangu- 
lations by the Van der Weele method and the execution of the calculations was entrusted 
to the Vienna Centre, the only one which had the possibility of carrying them out by 
means of an IBM 650 calculating machine. 
The uniform codification of the data has not been easy; it required much time and 
the constant collaboration of Mr. Neumaier, managing director of Bundesamt für Eich- 
und Vermessungswesen of Vienna. 
The results of these elaborations which are very interesting from a certain point of 
view and which deserve more careful investigations show a marked divergency as to 
accuracy. Owing to the very small number of comparable tests, the considerable differ- 
ence in procedures adopted and the lack of uniformity of the material used, it is difficult 
to analyse the real causes of this divergency by using the results available. 
Table Nr. 1 gives a synthetic summary of the results obtained in several Centres by 
using different photographic material. 
It is not possible to condense the fruit of such a complicated operation as aerial 
triangulation into a few representative indices; from a practical point of view the maxi- 
mum error of the coordinates of the control points is considered to be explicative enough 
as an index of the result obtained. 
The maximum residual errors of the three coordinates have been stated in table Nr. 
1, after a list of necessary information for an exact interpretation of the data of each 
conjunction. 
When the error (in m) is preceded by the sign + (or —), the course of the errors is 
very regular with a maximum in accordance with the marked value and a distinct pre- 
ponderance of positive (or negative) errors. 
When the number is preceded by the sign == the divergency of the errors is found 
in a strip having a width corresponding to the numeric value stated in the tables. 
Table Nr. 1 contains the maximum residual errors of the three coordinates of each 
conjunction after having carried out a compensation by the Van der Weele method. By 
this method, the repartition of the residual error is accomplished according to a law of 
third order. 
Besides, the diagram of the gross errors of a certain group of traverses has also been 
drawn. These errors can be defined as the residual errors after linear transformation of 
the coordinates of the strip transformed with two points chosen at the ends of the strip 
itself. 
Since the transversal rotations of the models have by no means been corrected, the