rial triangulation ought to be tested more detailed in practice. 
K. THULIN 
A bridging method with correction for influence of earth curvature and convergence in 
the individual model 
Introductorily the author gives some critical views on the photogrammetric theories, 
which up to now are used for bridging, especially the idea that the second model gets its abso 
lute orientation in 9 if the second photograph is fixed. The effect of the earth curvature on the 
single model and on bridging is discussed. Determining the convergence in a model in different 
ways is developed. Further methods are deduced to compensate for the effects of earths curva 
ture and convergence. By using these methods it is possible to obtain a total model of several 
photographs in a solid unit where height-errors of the second degree can be separated from tho 
se of the first degree. Determining and correcting of azimuthal deviation are discussed. Finally 
the possibility to compensate photographs for the effect of earth curvature is investigated. 
* 
* * 
Les communications annoncées par les PAYS-BAS à la réunion de Milan en 1962 : 
A. J. Van der Weele - Précision obtenue dans les compensations d'aérotriangulation, 
F. Ackermann - Détermination théorique de la densité des points d'appui en fonction de la 
précision désirée, 
I. T.C. - Influence de l'introduction des données auxiliaires sur la précision de l'aérotrian 
gulation, 
n'ont pas été confirmées à la présidence de la Commission III.