SANTONI SOLAR AEROTRIANGULATION - WORKING METHODS
ADJUSTMENTS AND RESULTS OF LATEST EXPERIENCES
by CARLO TROMBETTI
Military Geographic Institute, Florence
SUMMARY. — The latest studies and experimental works performed by I. G. M. and E. IL. R. A. in the
field of aerotriangulation with Santoni's methods, have
been intended to find out the working procedure most
suitable for its practical application (Premise).
It is established that Santoni’s method of aerotriangulation differs from other methods because the
imposition of the transversal and longitudinal tilt of each new photograph does not depend on the elimination
of the vertical parallaxes among some points of the optical model, but on the knowledge of the altazimutal
position of the sun and of the angular position of the camera axis with respect to sun direction at the mo-
ment of exposure. The analytical procedure and the special instruments are described, by which the above
mentioned inclinations can be determined from the data collected trough the solar photograph (
A critical examination of the special apparatuses (solar periscope,
chanical calculator) and the usual instruments (
chap. 1.).
solar photogoniometer, solar me-
Santoni camera mod. IV, Stereocartograph mod. IV) which are
needed for an aerotriangulation according to the Santoni's solar method, leads to the exposition o
f the draw-
backs and advantages shown by the experience (chap. 2.)
Entering into the actual carrying out of the experiment, the conditions of the exposures and ground
surveys are described. It is shown that as a result of ground survey the strip—
about roo km in length—disposes
of three terrestrial controls :
at the beginning, at the middle and at the end (chap. 3.)
From the field surveys, one passes to the preliminary calculations
of photographs.
and tests proceding the connection
Carefully described is then the research concerning the setting of the camera
with respect to the plotting instrument. This research is carried out on the pai
control, and leads to the determination of a constant — if there is any — to be ass
for all pairs (chap. 4.).
-periscope, on its whole,
rs provided with ground
umed as corrective factor
One enters the working details of the photographic bridging. The analysis of the nadiral photographs
connection comes to the noteworthy conclusion that it can provide the swing values of the intermediate
photographs for the subsequent calculations :
but it can not always provide a reliable value of the systematic
error in the tr
ansfer of swing. The tecnique of the solar, definitive connection is then exposed,
with the rough
results at the and of the strip (chap. 5.)
Passing to the selected method of adjustment, its informative criteria are outlined which can be sum-
med up as follows :
19) — The systematic error, whatever it may be, is calculated according to its effects inside the last model.
2°) — According to the entity and sign of the deformation which is examined in that model, the systematic
corrective factor is calculated, and then the strip adjusted.
3?) — The residual closing errors, referred to the geodetic net, are ascribed to accidental errors, and adjusted
linearly.
The acquired results show, in the present case, a heavy influence of accidental errors mostly due to
the photographic definition. The solar method supplies, in cases like that, the possibility of reducing several
bridges of the same aerea to a sole angular bridge, se that the influence of the residual accidental errors can
be put in evidence independently from the angular setting of the cameras. It follows th
at their influence may
be reduced by taking the mean of the various connections.
The final results prove that the solar methods
allows also removing «a posteriori » many troublers of photographic views (chap. 6.)
