Result = extentofview(classes, nrdirections)
non spatial scalar
spatial boolean, nominal, ordinal
distance is measured in true distance (default)
distance is measured in number of cell lengths
For each cell and for each direction this function determines the distance untill a cell with a different value than the current cell value is encountered. For each cell these distances are summed. To calculate the average distance, divide the result by the number of distances. This average extent of view can be used as an indicator for the openness of the landscape, for example.
This operation belongs to the group of Neigbourhood operator; operators for visibility analysis