. 
Conclusions 
From the reports from different parts of the world included in this 
report of the Working Group it can be learned that the application 
of Photogrammetry to Highway and Railway Planning and Design today 
is regarded as a conventional technique. There are, however, still 
great differences in the level of application between different 
countries. One of the reasons may be that although there do exist 
effective systems of the combination of Photogrammetry with other 
Sciences as Surveying, Electronic Data Processing and Automatic 
Plotting, the importance of an effective introduction and training 
has not been taken into account. 
The practical application of the Digital Terrain Model Technique to 
Highway and Railway Planning and Design is so far very limited with 
the exception of a few countries. There do exist many different DTM:s 
all over the world based upon different philosophies concerning the 
data acquisition and the interpolation, but the technique seems to 
be better fitted to the planning and design over limited areas as 
for road interchanges, residental and industrial areas, browncoal 
mining, than over the long and narrow corridors, which are actual 
for Highway and Railway Planning and Design. The acquisition of topo- 
graphical data by photogrammetric or by terrestrial methods does not 
longer create any important problem for the DTM or for the Semiauto- 
mated Mapping technique as the development of automatic registration 
equipments is very active. The main problem seems to be the checking 
of the content of the model in an effective way before the applica- 
tion. The development of interactive displays etc, will, however, 
contribute to a solution also of this problem. 
It is also important to include in the conclusion a few words on the 
importance of the introduction of.the simple tools in the form of 
deskcalculators and plotters as a complement to the big computors 
and plotters for the manipulation of the topographical data. These 
aids have a great psychological effect for the introduction and 
acceptance of an improved technique. The engineers must have the 
possibilities of playing over a wide register of aids also in his 
own office in order to be able to fulfil his complex work.