A rather relevant fact is that analytical aerial triangulation has furthermore im- 
posed itself at the same time, both in the field of triangulation per strips and in the one 
of triangulation per blocks. 
It is not meant to enter into details of a scientific nature relating to this subject 
in this Report, but, almost as a comment of what will be said elsewhere about the scien- 
tific problem of analytical aerial triangulation, it is indispensable to underline the con- 
siderable value of the complex technical activities carried out about this subject. 
Looking through the aforesaid tables, where it is possible to find a far greater and 
more interesting number of details, it is advisable to say that not less than 5 Organiza- 
tions have already experimented such a method applied to the single strip, and that 
5 other Organizations have applied or are about to experimentally applying the analy- 
tical aerial triangulation to the problem of blocks. 
Amongst the latter ones, there is one Organization and precisely the English 
Ordnance Survey who has already applied this proceeding for the production of maps 
of a medium scale, with very good results. 
The greatest interest concerning this new technique, is evidently based on the 
advantages of an economical nature and on those of precision it can bring. 
It 1s obvious that it is still quite impossible to give a statistically convincing ans- 
wer to this problem. The figures reported on the table, both concerning the lasting 
time of the operations and the consequent yielding-value of the method, and concern- 
Ing precision, are extremely varying but are above all mutually impossible of com- 
parison. 
In a particular way, concerning precision, besides the numerically very interesting 
data of the Ordnance Survey about the precision reached in the analytically triangula- 
ted blocks, it must be remembered that, at the Ohio State University, at the Centro 
di Addestramento e Studi Fotogrammetrici of Milano and at the National Research 
Council of Ottawa, the precision reached by analytical triangulation is about of the 
same order as the one reached by instrumental aerial triangulation. 
The questions raised by this simple observation are of enormous importance, but 
owing to the scanty number of experiments carried out, they will obviously remain 
for the present, without any reply. 
Amongst the several questions that are asked, the following is the most urgent 
one: « Has the maximum point of precision allowed by photographic material employed 
for this work, really been attained? » 
It 1s necessary to recognise the fact that, to the instrumental and operating pro- 
gress concerning analytical aerial triangulation, does not correspond a similar adapta- 
tion of proceedings, instrumentations and technique of taking photographs. These 
are still those of the usual aerial triangulation quite apart from a definite greater num- 
ber of studies made on plates, instead of on films. 
It 1s possible that the remarkable development of this new proceeding will bring 
about, in future years, a notably decisive and upsetting pressure also, especially in 
this sector. 
In the same way, the instruments supplying auxiliary data on photograph orien- 
tation whose use, in analytical triangulation, has already been studied and experimen- 
ted at the « Centro di Addestramento e Studi Fotogrammetrici » of Milano. shall have 
to become adapted to the demands for more precise information coming from those 
employing analytical proceeding. 
About other partial novelties which do not deeply affect aerial triangulation pro- 
ceedings, we shall talk during the analysis of the single working-proceedings now 
following. 
14 
the ins 
by a vi 
point o 
present 
for whi 
per str 
scale c: 
Ve 
if long, 
groups. 
In 
among 
Mc 
mainly 
El 
of poin 
cient n 
Th 
a bette 
vation- 
positioi 
one ob 
As 
precisic 
large n 
In 
consent 
It 
right is 
in the: 
| 
lation | 
Fl 
to be 1 
Th 
attemp 
Ab 
strips 1 
made a 
Hi 
experin 
Th 
triangu 
mentiol