100 COMMUNICATION OF PROF KONSHIN
2ß = 130° for flat country to a focal point of
200 millimetres, that is 2 5 — 60° for high
mountains.
The specification for the longitudinal over-
lap is 80 per cent, in order to provide for two
independent vertical control bridging processes.
Transverse strips should be flown every 50 kilo-
metres, so as to produce close circuits of radio
geodetic data. The data furnished by the radio
geodetic stations as well as those of the radio
altimeter or of the statoscope are recorded both
on the main and on the transverse flights. Ho-
rizontal ground control comprises the determi-
nation of the ground station co-ordinates.
Geodetic altitudes are determined for four
points for aerial photographs at intervals of 10
to 12 stereo pairs along each strip. Afterwards
the plane co-ordinates of the nadir points of the
main and transverse strips are determined. The
co-ordinates within every closed circuit are ad-
justed and horizontal photogrammetric networks
are built up from the photographs of the main
strips, with simultaneous adjustment of photo-
grammetric and radio geodetic co-ordinates.
Aerial triangulation is carried out either by
optical, mechanical or analytical methods. In
the case of the latter, electronic computors of
the Ural type are beginning to be used. In aerial
triangulation by optical and mechanical instru-
ments or in mapping photogrammetric instru-
ments are used based on the principle of pro-
cessing the photographs by means of transform-
ing the columns of projecting rays. The univer-
sal instruments of this type — that is Romanovs-
ky stereo projector and Drobychev stereograph
_ have an instrument error of about 1 to 12,000
of flight altitude.
In the USSR colour aerial photography is
widely applied. The materials being of the two
or three layer type. They increase the interpre-
tation quality of the photographs. Soviet experts
consider that the methods and instruments de-
veloped in the U S S R facilitate the mapping of
their country, but this does not preclude the
necessity for further improvement.
Monsieur J. CRUSET: Je remercie le profes-
seur Konshin de sa communication. Je pense
que la partie la plus intéressante est celle qui
concernait le sujet déjà traité par Monsieur
Corten, et j'invite bien entendu le professeur
Konshin à se joindre aux personnes qui, salle
61 à 13.30 hrs., discuteront la conférence de
Monsieur Corten. Puis-je renouveler le souhait
que j'avais fait à Stockholm lorsque le profes-
seur Konshin a parlé pour la premiére fois au
sein de la Commission I, de voir l'Union So-
viétique constituer une société nationale de pho-
togrammétrie et la voir adhérée à la Société In-
ternationale de la Photogrammétrie, et partici-
per à l'Exposition d'instruments. Une conver-
sation que j'ai eue avec Monsieur le professeur
Lobanov laisse espérer qu'il en sera prochaine-
ment ainsi.
Permettez-moi maintenant de donner pour
un instant la présidence au secrétaire Monsieur
Baudrimont, pour que je vous dise quelques
mots du sujet dont j'étais chargé.
SOCIE
[X me C
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