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B - INQUIRY ON AERIAL TRIANGULATION APPLICATION 
1. — AIM OF ENQUIRY 
The premisses, enunciated in the previous paragraph, are mainly aiming at in- 
troducing and justifying the one-sided address purposely given to the Commission’s 
enquiry on the applications of aerial triangulation. 
This address is mainly based on the assumtion that the Commission's report 
must also be an up-to-date source of thecnical news, the most complete mirror of 
the practical work carried out in the aerial triangulation field, a sufficiently detailed 
casuistry of the problems which have been faced, of their variants in different places 
and local situations and therefore of the different procedures by which they have 
been. solved. 
In this extremely varied description, as outlined, we shall not fail to note later 
on the clear outline of the new general tendencies, the new incentives given to ope- 
rative practice by scientifical research as well as the impulses given for practical ne- 
cessities continuously to science with a view to solve and study some well defined 
problems. 
In fact, the aim of the report writers is exactly to point out all these ways and 
tendencies, as they appear from the actual present-day situation. 
The indispensable premiss for such information-enquiry 1s a vast gathering-up 
of news data. The normal method of securing such a collection of data is through 
the despatching of a questionnaire. 
The questionnaire sent out by this Commission to over 130 addresses comprising: 
all Commission IIl’s National Rapporteurs; all National Societies, Members of I.S.P. 
and to a great number of aerial triangulation experts of various Countries, is divided 
into two sections. 
The first part is reserved to news and information of a general kind related to 
each country, while the second part contains questions of a more precise and detailed 
character, concerning above all practical works carried out on aerial triangulation. 
For the sub-division of the matter, we followed the aforesaid criterion. 
Aerial Triangulation is sub-divided into two types, namely: 
2.1. — Triangulation per strips 
2.2 — Triangulation per blocks 
which, in their own turn, are also sub-divided into: 
1) instrumental method triangulation 
2) analytical method triangulation 
3) radial method triangulation 
Each one of the six deriving classes contains different group-questions, each one 
of which refers to the sequence of operations conducted in working out aerial trian- 
gulation: 
a) flight and characteristics of ground control points 
b) bridging of photographs 
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