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AERIAL TRIANGULATION WITH AUXILIARY DATA, BRANDENBERGER 93
Switzerland
According to the report of Professor Zeller and Mr. Schlund from Switzerland only
statoscope data are used as auxiliary data in this country. It is considered that aerial
triangulation with statoscope data yields control points with an accuracy sufficient for
mapping in scales 1: 20,000 and smaller. A new method of strip triangulation with sta-
toscope data was investigated, namely the method of independent stereo pairs (photo-
graphs with 70 percent overlap; models 1-2, 3-4, 9-6, etc, overlap with 10 percent; these
models are considered as independent stereopairs and are triangulated at the Wild Auto-
graph A-7 using statoscope data and transfer points in the overlap between adjacent
models; see dissertation Helmy). Statoscope data was also used in the experiments for
O.E.E.P.E., Commission B using the conventional aerolevelling method. The method of
independent stereopairs was applied to the block “Vercors” (machine-coordinates were
recorded on punch cards and strip and block adjustment was carried out by means of an
electronic computer). Also, the method of strip triangulation with statoscope data and
independent geodetic base lines was studied (dissertation Karara). Auxiliary data from
Santoni's sun-periscope are considered to be used in the future in connection with new
tests to be carried out for O.E.E.P.E., Commission B. In case that strip triangulation
with statoscope data is carried out according to the aerolevelling method this is done by
using well-known procedures published by Brandenberger, Helmy, Karara and Zeller (in-
troduction of fixed bz-values according to the statoscope data in the first order stereo
plotting instrument; relative orientation with both ¢). For the strip adjustment 3 to 5
ground control points are used in the first model.
In addition to that 3 ground control points in the middle and at the end of the strip
must be available. Several strips with statoscope data were triangulated and adjusted
according to the above indicated procedures. The following standard residual errors were
obtained.
Strip 1: 52 km, A — 8000 m above gr., Wild RC.7 Aviogon,
Wild A-7, 9 independent pairs; m,= +217 m,
m, = = 3.0, m,=*25m
Strip 2: 82 km, h = 4800 m above gr, Wild RC.5 Aviogon,
Wild A-7, 20 independent pairs: m, = — 4,7 m,
My = =3.7 m, m= +25 m
Strip 3: 87 km, h = 4800 m above gr., Wild RC.5 Plate-Adapter,
Wild A-7, 32 models, aerolevelling: m, = = 3.2 m,
m, = =2.1 m, m, = + 40 m
An average time of 11 to 2 hours was required per model when the aerolevelling
method was used. For the method of independent stereopairs 3 to 4 hours was required
per model. Professor Zeller and Mr. Schlund state that there is no significant difference
in costs when aerial triangulations with or without statoscope data are compared.
United States
From the various reports from the United States follows that several organizations
are concerned with aerial triangulation using auxiliary data. For instance Lt. Col. Ahma-
jan reports that at present at the Army Map Service a test is being conducted employing
Airborne Profile Recorder (APR) over long flights up to 300 miles in length. Vertical
photographs were flown at altitudes of 20,000 and 30,000 ft. above sea level. Also
SHORAN is used for the planimetric positioning of aerial photographs. SHORAN data
is used in three forms namely for positioning of every exposure station, for controlling
of cross-flights only and for positioning of secondary control points. The methods used
with APR are similar to those developed at National Research Council in Canada; how-
ever, the aeropolygon method is also being tested with APR. SHORAN-controlled photo-
