e 
Although at least one model has been developed with the capacity to 
store subsurface characterestics eg strata boundaries, such facili- 
ties have been little used because of difficulties in getting and 
interpreting geological data. 
There is some interest in the United Kingdom in persuading contractors 
to accept as bases for payment earthworks quantities calculated by 
using digital ground models; such.acceptance would greatly simplify 
working-site procedures as both contractor and engineer have at 
present to re-survey the site in order to solve any differences of 
opinion about quantities. However, the matter has not yet progressed 
far enough to predict the widespread adoption of such a practise. 
The status described above was reported by Dr J.P. Stott, Transport 
and Road Research Laboratory, Department of the Environment, England. 
In a report KFK-CAD 3 from the Institut für Anwendungen der Geodasie v 
im Bauwesen, Stuttgart, West Germany, Dec 1975 Mr H. Bopp et al presents 
"A Digital Description of Design Parameters for Optimization of High- 
way planning", the following as a summary: Optimization techniques 
are becoming important aids in the design phase of highway planning. 
At the Institut für Anwendungen der Geodäsie im Bauwesen, Stuttgart, 
SCHEK has developed a method of optimizing road alignements in posi- 
tion and elevation simultaneously. His ideas have led to the investe- 
‘gation of special problems associated with a digital description of 
design parameters. The optimization method is improved by the in- 
corporation of a digital height model and by methods for generating 
a gradient-surface and an evaluating-surface model. Furthermore, a 
technique fo smoothing out meander effects, which occur after the 
position or the elevation of an alignement has been altered, is deve- 
loped. Nothing has so far been reported concerning the introduction 
of the technique in the practical design work. 
In Bildmessung und Luftbildwesen, Heft 3 May 1975, some reports on 
the Germàn progress on the development of the DTM-technique were + 
presented. One report by mr H Fucks, Cologne, deals with the prac- 
tical application of the DIM, consisting of an elevation and a si- 
tuation model, to the Rhenish Browncoal mining. The DTM is used 
for the description not only of the area, but also of numerous de- 
marcation areas of the coal seams and stone layers. 
Semiautomated Photogrammetric Methods 
Another interesting trend of development that may be of importance 
for the further development of the planning and design technique 
concerns the Semiautomated Photogrammetric methods. This technique 
implies a digitizing of the content of the photogrammetric model so 
that it can be used for graphical output in the form of maps, or 
for numerical output in the form of a DTM or for the preparation 
of an orthophoto. 
The first systems in productive operation were reported from Rijks- - 
vaaterstaat in Holland for the preparations of planimetric maps and 
from the Ontario Department of Transportation and Communications in 
Canada for large scale topography mapping. The development of the 
technique has been busy in different parts of the world but any new 
systems in practical operation for highway or railway purposes have 
so far not been reported to the Working Group. 
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