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OEEPE, COMMISSION B 39 
maximum values of the gross errors stated in the table have been calculated at the only 
control points placed near the axis of the strip. 
The Chairman of the Commission, Ing. D. Belfiore has also carried out the compen- 
sation of some strips by a compensation method of errors according to a curve of second 
order (Von Gruber method). 
The coefficients of the expressions given by the corrections have been obtained: first 
by taking only into account the known points which have been placed at the ends of the 
strip and secondly by also taking into account a known point in the centre of the strip 
itself. The maximum residual errors of the strips compensated according to these criteria 
are contained in the last 6 columns of the table. 
The total impression of all data gathered in table Nr. 1 gives rise to the following 
general considerations: 
Most triangulations carried out and compensated show residual errors in Z which 
are greater than those in X and Y. : 
It is evident that the values of the maximum residual errors of the three coordi- 
nates depend on the number of connected aerial photographs. 
The compensation by the Van der Weele method has sometimes led to a remarkable 
improvement of the results; nevertheless, the part of the operation has been negligible in 
several cases, whereas the compensation by formulae of second order has brought a more 
marked improvement of the definitive data. 
The statistical validity of these conclusions is considerably reduced by the restricted 
number of comparable data which are available. 
The work carried out during this first stage has confirmed that which had already 
been anticipated; i.e. aerial triangulation offers remarkable possibilities of application 
in the field of large scales. 
This conviction has helped the Centres, the Members of the Commission and Ing. 
Belfiore, former Chairman in this effort: our best thank for their work. 
The interest of these studies has made us project and prepare a new cycle of tests 
for Commission B whom we consider most competent to contribute to the organization of 
the current investigations by using the valuable experience of the first work stage. 
First of all, thanks to the initiative of the Institut für Angewandte Geodäsie of 
Frankfurt, a new experimental polygon has been prepared in the south-east zone of 
Stuttgart which has been called: Reichenbach polygon. The polygon itself consists of two 
overlapping parts, which, however, form independent elements in a singular way. 
The first one is composed of a zone of 9 X 7 km? of a very hilly terrain where the 
maximum height differences amount to approx. 200 m; the Institut für Angewandte 
Geodäsie has determined a considerable number of terrestrial points in this zone. 
The second one consists of a long strip of 25 X 8 km? orientated south-east north- 
east partially covering the preceding zone: a more restricted number of terrestrial points 
has been fixed there. 
During spring 1959, flights have been carried out over this polygon by the collabo- 
ration of several countries which form part of the O.E.E.P.E. You will find the plan of 
flights carried out in table Nr. 2. 
The flights from 2.1 to 2.6 have been carried out over the small polygon; the flights 
from 3.1 to 3.5 over a strip of 25 km long. 
The basic novelties of these flights are as follows: 
the flights 2.1, 2.2, 2.3, 2.5 and 2.6 are real blocks of strips which can be used for 
large scales. 
The flights 3.1, 3.2, 3.3, 34 and 3.5, even if they do not form real blocks of 
strips, are, for the first time in the organization, a valuable material for investigations 
on medium scales. 
It has been considered useful and interesting to try the application of the auxiliary