$$AREA_{SD} = sd(AREA[patch_{ij}])$$
where \(AREA[patch_{ij}]\) is the area of each patch in hectares.
AREA_SD is an 'Area and Edge metric'. The metric summarises each class
as the standard deviation of all patch areas belonging to class i.
The metric describes the differences among patches of the same class i in
the landscape.
Because the metric is based on distances or areas please make sure your data
is valid using check_landscape.
Behaviour
Equals AREA_SD = 0 if all patches are identical in size.
Increases, without limit, as the variation of patch areas increases.