$$PRD = \frac{m} {A} * 10000 * 100 $$
where \(m\) is the number of classes and \(A\) is the total landscape area in
square meters.
PRD is a 'Diversity metric'. It is one of the simplest diversity and composition measures.
In contrast to lsm_l_pr, it is a relative measure and following, comparable
among landscapes with different total landscape areas.
Because the metric is based on distances or areas please make sure your data
is valid using check_landscape.
Units
Number per 100 hectares
Behaviour
Approaches PRD > 1 when only one patch is present and the landscape
is rather large. Increases, without limit, as the number of classes increases and the
total landscape area decreases.