EuroSDR Projects - Host Ireland

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Figure 4-13: Orthophotos of study areas in Switzerland
Two data sets were used as reference data. One is a land use data base (VECTOR25) covering ten classes (urban,
forest, orchard, shrubs, river, lake, wetland, gravel, rock and a class called other which seems to refer to open
areas). In addition a road network was available as a vector data set. This was converted into polygon format using
data on street width, provided with the data set, and incorporated in the land use data base (Figure 4-14 a-c). The
road data was included as otherwise most roads would be shown as change in the change map. When the land use
data is compared to the orthophotos, it can be seen that the reference data is very generalised, especially in urban
areas.