$$PLADJ = (\frac{g_{ij}} {\sum \limits_{k = 1}^{m} g_{ik}}) * 100$$
where \(g_{ii}\) is the number of adjacencies between cells of class i
and \(g_{ik}\) is the number of adjacencies between cells of class i and k.
PLADJ is an 'Aggregation metric'. It calculates the frequency how often patches of
different classes i (focal class) and k are next to each other, and following is a
measure of class aggregation. The adjacencies are counted using the double-count method.
Behaviour
Equals PLADJ = 0 if class i is maximal disaggregated,
i.e. every cell is a different patch. Equals PLADJ = 100 when the only one patch
is present.