European Organization for Experimental ... - Host Ireland

Experience of the digital monoplotting flowline at Ordnance Survey has shown that a mono
image is not as good as a stereo image for capturing the detailed juts and recesses and divisions
of housing.
This suggests that this form of image would only be suitable for capturing buildings for
1:10,000 or smaller-scale topographic mapping, where some generalisation takes place.
However, in dense city-centre areas, it is likely that stereo imagery would be necessary for
all building extraction.
To aid in the appreciation of the problems associated with this imagery, below is a comparison
between the IKONOS image and the aerial ortho-images supplied for this trial. These
are in the urban scene of Area 1 (see Figure 3 and Figure 4).
Figure 3: IKONOS image of the urban test area
Figure 4: Aerial photograph of the urban test area
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