90 AERIAL TRIANGULATION WITH AUXILIARY DATA, BRANDENBERGER 
regard to the presently existing devices for recording auxiliary data, however, it has to 
be stated that not many of them reach this goal. 
Progress report on aerial triangulation with auxiliary data in various countries. 
Canada 
Mr. Blachut from Canada reports that in his country only two types of auxiliary 
data are used in connection with strip triangulation, namely: 
a. Radar profile elements and 
b. fore or aft oblique photographs. 
Radar profile elements are used in the Radar Profile Method. This method was ap- 
plied to a strip 200 km long and flown from 10,000 m altitude triangulated in a first 
order stereoplotting instrument. The following standard residual errors were obtained 
after strip adjustment: 
  
  
= + 5 = + AR 
m, —2.5m, m,-— t6 m. 
To control the y-error propagation oblique photographs are used. From these photo- 
graphs straight lines in flight direction are transferred to the individual photographs of 
the strip triangulations. For this purpose a Straight Line Plotter was built. Radar profile 
elements are either directly used in the plotting instrument or for the strip adjustment 
while the information from oblique photographs are exclusively used for adjustment 
purposes. The strip adjustment is performed by using only one given ground control 
point at each end of the strip. This means that this method is principally developed to 
EE Ser 
  
determine points on the axis of the strip. From Mr. Blachut's report furthermore follows | 
that for the Radar Profile Method about 45 minutes is required per model and that the | 
costs of this method are comparable to those of the aeropolygon method since the addi- | 
tional work involved in processing the Radar Profile data is compensated by a simpler 
and more reliable adjustment procedure. 
Finland | 
From the report of Dr. Erola from Finland follows that auxiliary data is used from | 
horizon cameras. To improve this method a new type of horizon tube has been ordered 
from the Wild Company. The individual photographs of a strip triangulation are oriented 
in a first order stereo plotting instrument (Stereoplanigraph Zeiss C-5) according to the 
tilt components obtained from the horizon photographs. The remaining Y-parallaxes are 
eliminated equally by changing the position of both vertical photographs in the instru- 
ment. Two to four ground control points are available for an area of 100 km? and addi- 
tional vertical control points are given in a strip, 15-20 km apart. The flying height of the 
strips amounts to 4000 m and the individual Strips contain 15 to 40 models. The vertical 
photographs are taken with a Zeiss RMK HS 10/18 X 18 em camera. Strip triangulations 
are individually adjusted and the obtained coordinates of common points in the sidelap 
between adjacent strips are compared. From this comparison the following standard re- 
sidual planimetric errors are obtained : m, or m, = = 2 to 3m. About 11 hour per model 
is used for this strip triangulation procedure. Dr. Erola states that without the use of 
auxiliary data much more ground control points would be required which would make 
strip triangulation much less efficient. 
  
  
  
France 
In France (Institut Géographique National, report by Mr. Bonneval) the statoscope 
is used to procure auxiliary data. The Institut Géographique National also possesses an | 
airborne profile recorder which has, however, not been used up until now. Furthermore, 
this organization is considering the use of a gyroscopic recorder to yield lateral and 
  
  
  
  
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