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REPORT OF THE SESSIONS OF COMMISSION III
AERIAL TRIANGULATION AND ITS APPLICATION TO GEODESY
President: Prof. Dr. P. Wiser
Chargé de cours à la Faculté Polytechnique de Mons (Belgique).
Secretary: Ir A. J. van der Weele,
Chief of Survey Department, Ministry of Public Works, Delft,
Netherlands.
FIRST SESSION
Friday September 5th 1952, 9.05— 12.00.
The president welcomes the attendants, expresses the hope that the sessions
of Commission III may be successful and gives some information about the
places in literature where the papers of this session may be found, either
complete or summarized. The president regrets that Mr. Wassef (Egypt), who
prepared two papers, cannot attend the congress. It is also regrettable that
several active European photogrammetrists could not afford the long voyage
to Washington. He announced that Mr. David Landen would be so kind as to
read them.
Following the introduction the president asked Mr Landen to read Mr.
Wassef’s paper on “Some Aspects of Planning, Analysis and Presentation of
Photogrammetric Tests.”
“A few years ago the United Nations Organization published a report on
the state of mapping in the world which leaves no doubt that air survey is the
only tool which can cope with the prospective schemes. The extensiveness
of these schemes makes it all the more important that individual projects
should be planned in the most efficient manner. There is, however, no simple
criterion of efficiency: It is important to take into account the time factor,
labour conditions, accessibility of the area to ground survey, the allocated
funds, and so on in addition to the accuracy of the final maps. The issue is
always to find out the method, or combination of methods, which give the
required accuracy as economically as possible. The difficulties which one often
meets in choosing suitable techniques could, in my opinion, be avoided, or at
least much reduced, by better planning of the experimental work which has
so far been carried out, in order to avoid occasional incomplete or inaccurate
conclusions.
It is obvious that no limited amount of experimentation can lead to 100
per cent correct conclusions. It is, however, very unlikely that experience will
seriously contradict the conclusions which are properly drawn from properly
designed experiments. On the other hand, non-objective or partisan experi-
ments, which are apt to be disqualified by experience, are invariably either
inaccurate or incomprehensive. This, I think, explains why many a technique
failed in the test of time. Modern statistics have done much to show how to
improve the yield of our experiments in two ways: first, by increasing the
amount of reliable information that can be obtained from a specified number
