eik = total length (m) of edge in landscape between patch types (classes) i and k; includes landscape boundary segments involving patch type i.
dik = dissimilarity (edge contrast weight) between patch types i and k.
A = total landscape area (m2).
Description CWED equals the sum of the lengths (m) of each edge segment in the landscape multiplied by the corresponding contrast weight, divided by the total landscape area (m2), multiplied by 10,000 (to convert to hectares). Edge segments along the landscape boundary are treated like background (as specified in the edge contrast weight file) unless a landscape border is present, in which case the boundary edge types are made explicit by the information in the border. Note, total landscape area (A) includes any internal background present.
Units Meters per hectare
Range CWED ≥ 0, without limit.
CWED = 0 when there is no edge in the landscape; that is, when the entire landscape and landscape border, if present, consists of the corresponding patch type and the user specifies that background edge be given a zero-contrast weight (d = 0). CWED increases as the amount of edge in the landscape increases and/or as the contrast in edges increase (i.e., contrast weight approaches 1).
Comments Contrast-weighted edge density standardizes edge to a per unit area basis that facilitates comparison among landscapes of varying size