simultaneously interpreted e.g., a 50 micron image is 
obsered in stereo in combination with a 200 micron 
stero partner. 
In order to clarify , whether the imagery generated 
by digitisation of aerial photography is characteristic 
for the topographic mapping task, using CCD 
scanners, of course additional imagery has been 
interpreted. As a sample, in figure 5 is shown the 
comparison of the interpretation of a Spot image of 
the City of Hannover (Germany) with the existing 
linemap of the original scale 1:25 000. Figure 6 
shows the result of the suitability of Spot data for 
features to be shown in an ecological map of the 
scale 1:10 000. 
A more sophisticated comparison shows, 
photographic images are more than competitive with 
existing digital methods. 
Contrary to aerial photography radar images cannot 
properly be interpreted to derive the required 
topographic features, even though particular features 
relativley clear appear, such as metallic 
objects(fences, power lines vehicles etc), as well as 
rvers. The role of radar images should be more a 
supplementary part or exceptional exclusive for 
permanent clouded areas. 
  
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Figure 5: Comparison of the interpretation of a Spot 
image of Hannover with an existing line map