Here the author observed that recent develop- 
ments indicated the possibility of substantial 
reductions in vertical control requirements when 
using auxiliary data in simultaneous photogram- 
metric block adjustments. 
Tests had indicated that the bridging distance 
can be increased to the extent thät there is vir- 
tually no need for control points within the block 
for small and medium scale mapping purposes. 
Authors: Mr. H. Leppänen (Finland) 
Mr. I. Kukkonen (Finland) 
Title: The "MAPS" Data System for Map- 
ping Projects PP 111/136 
Here the authors presented a software package 
for block adjustment and geodetic calculations 
which makes possible a comprehensive data 
flow in topographical mapping. 
Author: Mr. A. Salman Gonzales (Mexico) 
Title: Development of Aerial Triangulation 
in CETENAL Mexico 
The author gave a report on the development of 
aerial triangulation in Mexico where extensive 
use is made of the polynomial adjustment of 
blocks developed by Mr. G. Schut at N.R.C., Ca- 
nada. 
The first paper of the session was given by Mr. 
Z. Parsi¢ from Switzerland. 
Presented Papers 
Author: Mr. Z. ParSiéó (Switzerland) 
Title: Ergebnisse einer Aerotriangulation 
nach unabhángigen Modellen am 
Autographen Wild A10: OEEPE Ober- 
schwaben-Block-Zürich PP //I/44 
Mr. Par$i¢ presented results from independent 
model triangulation using the Wild Autograph A 
10. Location of projection centers on an analogue 
plotter and various control point configurations 
were evaluated in tests performed with a portion 
of the Oberschwaben test area. 
A comparison was made between the results of 
aerotriangulation using targeted points and trans- 
ferred points. The two methods proved to be 
equally accurate. 
Dr. F. Ackermann (F.R.G.) intervened by observing 
that in planimetric adjustment more accurate 
results were obtained with transferred points than 
with targeted points. Mr. ParSió answered that 
this was probably due to the difference between 
the sizes of the measuring marks and of the 
points to be measured. The ratio was 1:1.2 for 
the transfer points and 1:0.8 for the targeted 
points. 
Authors: Dr. J. Albertz (F.R.G.) 
Mr. W. Kreiling (F.R.G.) 
Mr. J. Wiesel (F.R.G.) 
Title: Weitere Untersuchungen zur Block- 
triangulation ohne Punktübertragung 
PP 111/02 
Dr. Albertz with Mr. Kreiling and Mr. Wiesel had 
experimented with block triangulation without 
point transfer. Accuracies of 6 um to 7 um at 
image scale and elevations to within 1/1000 of 
flight elevation were achieved. 
The economy of this method is satisfactory, pro- 
vided that use is made of blocks with unusual 
overlap, foreward overlap =20% and side lap = 
60 %. Equally accurate results are obtained with 
this method as with conventional aerotriangula- 
tion. 
Colonel M. Datta (India) asked what the share of 
point transfer was estimated to be. Dr. Albertz 
replied that he was unable to give any detailed 
estimate of the role played by point transfer, 
having based his statement on rather crude data. 
Dr. H. Schmid (Switzerland) pointed out that the 
method here discussed differs from the use of 
conventional blocks only in what concerns over- 
lap. As regards the principle of analytical geo- 
metry, it is the same as the one applied in con- 
ventional bundle adjustment. 
Dr. R. Helmering (U.S.A.) asked how the results 
obtained were to be used in the subsequent 
mapping process. Dr. Albertz replied that they 
were used for the orientation of models. For this 
purpose suitable points have been chosen and 
measured simultaneously with the points to be 
used in triangulation. Intersection is used for 
the calculation of their coordinates.. 
Dr. H. Ebner (F.R.G.) asked whether aerial photo- 
graphy was not difficult with a forward overlap 
of 20% and a side lap of 60%. He also inquired 
whether manual exposure was required in the 
photography. Dr. Albertz answered that the slight 
deficiencies in matching that occur when photo- 
graphing without manual exposure cause no 
problem. 
Authors: Mr. M. Allam (Canada) 
Mr. C. Wong (Canada) 
Mr. C. Chaly (Canada) 
Title: Geometrical Distribution of Vertical 
Control and the Simultaneous 
Adjustment of Auxiliary Data in 
Independent Model Triangulation 
PP 111/06 ; 
A report was given of results of the use of aux- 
iliary data with independent model triangulations. 
The use of an Airborne Profile Recorder (APR) 
along and across flights and the use of lakes 
for auxiliary vertical control had yielded increased 
vertical accuracies and permitted increased bridg- 
ing distances. 
Mr. J. Gauthier (Canada), who read the paper, gave 
also some further information about the SPACE- 
M program. 
In the course of the subsequent general discus- 
sion, Dr. W. Faig (Canada) completed the state- 
ments made by Mr. Gauthier by observing that 
he had come to similar conclusions in his own 
work. 
Mr. J. Kure (Netherlands) said it was astonishing 
to hear that accuracy was improved with a reduc- 
tion of APR-points. He himself had experienced 
the contrary Dr. J Zarzycki (Canada) answered to 
this by saying that the poor points were removed, 
thus improving the quality of the final results. 
Author: Dr. A. Lobanov (U.S.S.R.) 
Title: Analytical Aerotriangulation and Its 
Application in the U.S.S.R. PP 111/38 
In the absence of Dr. Lobanov, Dr. |. Antipov 
(U.S.S.R.) reviewed analytical aerotriangulation 
in the U.S.S.R. Efforts had been concentrated on 
97