94
AERIAL TRIANGULATION WITH AUXILIARY DATA, BRANDENBERGER
graphs are triangulated to obtain elevations. By determining the coordinates for the
plotting camera nadir of each exposure station in the strip triangulation
these points according to the tangents of the angular cor
ment, the nadir points of the exposure stations can be approximately located
adjusted to the SHORAN positions of the exposure stations. By this
adjustment, the effect of the random errors in the SHORAN po
and shifting
rections of the vertical adjust-
sitions is
and then
photogrammetric
minimized.
Recent tests lead to the conclusion that altimetric data from barometers or statoscopes
should be used for presetting bz-values in the first order stereo pl
improve the vertical
cedure at first order
otting instrument to
accuracy of strip triangulation. When APR data are used the pro-
stereo plotting instruments consists of presetting the bz-values and
eliminating the y-parallaxes with the rotational movements. Scale transfer by means of
elevations of points established by APR. In case that SHORAN data are used the pro-
cedure at a first order stereo plotting instrument is as follows:
y-coordinates of the nadir points are obtained by summing the instrumental ba-
values. Instrumental
The instrumental x- and
and by-
%-, and y-coordinates of pass points are determined by recording
their %-, and y-coordinate differences with respect to the preceding nadir points. These
nadir points are located at the instrument by moving the base carriage in such a way
that the floating mark appears in a vertical through the perspective center
ment camera in question (zero position).
of the instru-
In the Institute of Geodesy, Photogrammetry and Cartogra hy (Professor A. Bran-
1 1
denberger) of the Ohio State University extensive tests were carried
the accuracy of SHORAN-controlled air stations. These tests were
way that the SHORAN-controiled exposure stations of vertic
determined from these photographs using a sufficient number of ground control
(9" X 9"/6"
out to determine
performed in such a
al photographs were directly
points
Metrogon Photography, resection in space with least square adjustment, test
carried out by Dr. S. Laurila). The following standard residual errors for the SHORAN-
determination of the exposure stations were obtained: m = M
length = 225
y
M
x
- Tm (SHORAN base
km, average distance of the exposure stations from the SHORAN base
160 km, altitude of the exposure stations = 6000 m above gr.). At present a strip trian-
gulation with statoscope data (Laufen, Switzerland, Wild RC 7-a photography) and a
block triangulation with statoscope data (block Vercors, Switzerland, Wild RC 7-a pho-
tography) are being carried out. New systems of block adjustment were
the adjustment is done by using the IBM 650 Electronic Computer. Also,
strip triangulation (Phoenix, Arixona to Los Angeles, California, 9" X 9" 6"
Photography, flying height 12 km above gr., length of the strip 63
of strip 11,000 km?) was triangulated at the Wild Autograph A-7. Although no auxiliary
data were
developed and
a super long
Metrogon
0 km, 80 models, area
available this strip was triangulated according to the principle of aerolevelling
(bz = 0 method). The purpose of this test was to prove that long strip triangulations
performed by the aerolevelling method yield much smaller
with the aeropolygon method. The following closure errors were obt
[o
strip triangulation (bz
A-7, Herget Method, test carried out by Professor Doyle and Mr.
principle of aeropolygon and the following closure errors were found: Ax
: 0 method):
2200
m.
ly
closure errors when compared
300
m,
1
strip was also triangulated by the analytical method (measurements at Wild Autograph
ained for the 630 km
10 m. The same
Mahoney) using the
4800 m,
4, — 6000 m, I, = 41,400 m (this last closure error is much larger than expected and
can be only explained by assuming that the distortion curve of the Metrogon lens did not
show with sufficient accuracy the actual distortion). Since this strip tri
angulation cross-
es areas with individual state coordinate systems it was necessary to determine the
planimetric closure errors by using the astro-geodetic longitudes 1 and latitudes q of the
given ground control points at the beginning and the end of the strip. This was done in
such a way that in the case of the aerolevelling test 4 and y were converted by a con-
TEN me
coUe
