EuroSDR Projects - Host Ireland

spectral reflectance. Shadows (black) are visible in some parts of the image, especially close to large building
blocks and forest edges. The class other urban object (yellow) is here more related to bare fields and, as it is not
clearly defined, will be treated as such in the evaluation.
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Figure 4-18: Classification of German data set
For the comparison of the classification with the reference data a new evaluation matrix was set up to account for
the different classes of the ATKIS data base (see Table 4-9). Each class combination is assigned to one of the four
plausibility classes. As described above the combination of other urban object area in the classification and farmland
in the land use data is considered to be identical. The result of the evaluation is shown in Figure 4-19. Very
large areas are assigned to questionable. In most cases these are areas which are considered to be grassland in the
ATKIS data base but are actually covered by forest in the classification. Some areas where building activities had
taken place could be identified and are shown in red. Vegetation in urban areas is highlighted in yellow as are roads
along fields. Although most of these roads show up in the initial classification, they were later merged with fields in
the refinement of the classification. If these roads were to represent a problem when using the change map, they
could be removed by including the first classification stage in the evaluation.