ela
is
T
x
me
so
egy
FES
s
E is
RE
LEG RR
RT
4
by photographing the sun at the instant of exposure. The accuracy of this me
to be 3’-4".
As to the many numerical methods of tilt determination on the basis of meas;
in the pictures, we limit ourselves to mentioning the method described in [18
method, which requires merely a mirror-stereoscope and a parallax-bar for
x- and y-parallaxes, the x- and y-tilts are determined with an accuracy
0.5:10:1.70.
On the basis of all these data we assumed in our examples, fig. 1-9, à standar
of 10’ in the determination of camera tilt, a value that certainly is
representative for what can be obtained at present.
The investigations described in this paper lead to the conclusion that analytics
radial triangulation has a new future, thanks to the small camera tilts encountered in
photo-flights with modern auto-piloted aircraft, the development of modern m
stabilizing the camera or recording the nadir point and the availability of modern comput.
ing machines. It is not therefore surprising that a firm as Wild, Switzerland, has con-
structed a new stereoscopic radial triangulator. This instrument is distinguished from
earlier types in that it embodies a quite new principle: the photographs (
which may he
of a size up to 23 X 23 em? or 9 X 9 inch?) are in a fixed position and over each of they
rotates a glass scale provided with a row of measuring marks. To measure à direction
from the radial centre to a certain point, that pair of measuring marks which i
nearest to it, is set stereoscopically onto the point in question by rotating the glass scales
and shifting them over a very short distance of maximum only 21/, mm which is hy
the distance between two consecutive measuring marks of a row. The rotation angle is
read off a large circular scale with unarmed eyes very easily. Further particul
of course be announced as soon as the instrument is on the market.
hog Seems
€ments
]. By this
Measuring
of the order of
d error
a non-flattering
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Spatial
rra.
r
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na
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