EuroSDR Projects - Host Ireland

5.1.2 Qualitative Comparison
In addition to the numerical analysis, a qualitative comparison of special objects was performed,
because some participants classified more and detailed objects than others. The results of qualitative
comparison are shown in Table 6.
SAR image Optical image
Freeway detected detected
Main Road predominantly detected detected
Alleys few to none predominantly detected
Trenches none few to none
Lakes big = good, small = partially big = all, small = predominantly
Trees depends on interpreter, but possible separate ones mostly detected
Buildings big ones detected, smaller ones partially but not
always correct
big and small ones detected exemplary
Golf Course only one detection only two detections
Sports Field partially detected nearly all of them
5.1.3 Summary – Copenhagen
land use boundary, ruins, barracks, parking lots
Table 6: Qualitative Comparison of Copenhagen
The results of visual interpretation of Copenhagen show that big and continuous areas like forest,
agricultural and built-up areas were detected equally well in SAR and in optical imagery. Smaller
areal objects like lakes and separate buildings are more difficult to extract from SAR imagery.
Concerning linear objects it can be ascertained that highways and main roads were detected equally
well in both types of image. Smaller linear objects, such as alleys, trenches and secondary roads,
cannot be detected in SAR but partially in optical imagery. In addition, classification of roads versus
alleys appeared to be easier in optical images.
The golf course, which is placed on the left side of the images, was mostly detected as green corridor.
Only two interpreters of optical and one interpreter of SAR imagery classified that area as a golf
course. The classification of this area in the ground truth (reference) data could only be done well with
information from the topographic map.
The visual analysis shows that some interpreters used a more detailed classification than others. They
additionally detected land use boundaries, ruins, barracks and parking lots. These objects cannot be
approved with certainty, because there is no evidence for them in the available ground truth data.
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