The development of systems for the terrain-information is today accep- 
table for the two first phases of the design, and therefor the further 
efforts can be concentrated towards the final design phase. 
The existing systems will without discussion be more advanced in the 
future as the data processing technique developes, provided that the 
development of the photogrammetric principles is increased. The rese- 
arch work for increasing the quality of the photogrammetric data by 
correcting for systematic errors should be actively stimulated. The possi- 
bilities of introducing analytical photogrammetric methods are facilitated 
by the digital terrain model and as these principles can be of an essential 
value for increasing the photogrammetric accuracy they should be more 
developed in the coming period. 
The international interest and need for utilizing photogrammetry 
combined with other sciences in the highway design is very intensive. 
Therefor it should be a great task for the ISP to assist in the introduc- 
tion of existing results in countries where the methods are not yet utiliz- 
ed to a full extent and also to contribute to the further development 
towards more advanced system principles. 
Summary 
The intention of this paper has been to discuss experiences from the 
development of the application of photogrammetry during the period 
1964—68 in principles. The development in the different countries has 
not been discussed in details as they have been reported in different 
papers and at different occasions. Some of these reports are accounted 
for in the reference below. 
Another intention of the paper has ben to emphasize the importance 
of steering the development of photogrammetry into a system that in 
an effective way combines photogrammetry, geodesy, dataprocessing and 
automatic drawing. The systems and procedure must be logical and 
simple for having a chance to get accepted by the engineers. 
The importance of concentrating the further photogrammetric research 
work around the problems of the systematic errors is also strongly under- 
lined. 
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