Spatial metrics are calculated within the bounds of a geographic area. This area is called the spatial domain, a relatively homogeneous spatial entity that represents a basic landscape element. The definition of the spatial domain strongly influences the metrics and will generally depend on the aims of the study and the characteristics of the landscape. In MAMUD, two approaches to derive spatial metrics are examined. One method uses a city block as a basic unit for which metrics are derived. More specifically, the distribution and configuration of impervious surface fractions within a city block are reflected by the metrics. The required impervious surface maps were derived in WP2. For the other approach, the spatial domain is not fixed in advance but determined by the bounds of a window or kernel that moves over a land-cover map. At each position of the window, an algorithm called OSPARK compares the spatial configuration of the map's raster cells to predefined land-use templates.
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