$$PLAND = \frac{\sum \limits_{j = 1}^{n} a_{ij}} {A} * 100$$
where \(a_{ij}\) is the area of each patch and \(A\) is the total
landscape area.
PLAND is an 'Area and edge metric'. It is the percentage of the landscape
belonging to class i. It is a measure of composition and because of the relative
character directly comparable among landscapes with different total areas.
Behaviour
Approaches PLAND = 0 when the proportional class area is decreasing.
Equals PLAND = 100 when only one patch is present.