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accuracy for DTM mapping exist. Here is one 
from Hannover, where a 1 m DTM at 12.5 m 
spacing exists. 
The generated DTM over flat and hilly 
territory showed that DTM’s to ± 5 m are 
possible in flat areas, but that huge 
discrepancies occur in wooded and hilly areas 
where radar shadows and foreshortening 
occur. 
4. The scenario for the future 
The future of mapping lies without doubt in 
the capability to provide up-to-date base data 
for a Geographic Information System. 
Satellite images provide an economical input 
of georeferenced image data which should be 
merged with existing, old map data, which 
can eventually be geometrically corrected by 
the satellite data. 
If reliable base data are available the can be 
merged with thematic data obtained from 
satellites and from ground surveys to be of 
use to the planning authorities. 
A survey of existing GIS efforts at various 
scales based on a project orientation shows 
that survey costs alone are tremendously 
expensive per km 2 if not integrated. Cost 
benefit ratios of 1:4 can be achieved through 
data integration. 
In Germany base data are already being sold 
by the administrations instead of maps. 
Digital orthophotos compare favourable in 
price with vector data obtained by digitization 
of maps. New map compilation would be 
considerably more costly than the digital 
orthophotos. Thus map updating via on 
screen orthophoto digitization is an 
economical necessity. 
If satellite orthophotos at high resolution can 
be provided cheaper than those of aerial 
photos, then their market is clearly 
established. 
We have the new technology under control: 
■ GPS 
■ digital photogrammetry 
■ remote sensing 
■ GIS 
We must find organizational structures which 
permit integration of data. 
The mapping process with isolated specialists 
has to be transformed into a geoinformatics 
process meeting the demands of society in an 
efficient and economic manner. 
In this task WG VI/3- Technology Transfer can 
play a very important role. 
The problems faced by our new generation of 
mapping experts are less technical, but more 
organizational.