(C122) Connectance Index

connect_c.jpg  

cijk =   joining between patch j and k (0 = unjoined, 1 = joined) of the corresponding patch type (i), based on a user specified threshold distance.

ni =     number of patches in the landscape of the corresponding patch type (class).

Description

CONNECT equals the number of functional joinings between all patches of the corresponding patch type (sum of cijk where cijk = 0 if patch j and k are not within the specified distance of each other and cijk = 1 if patch j and k are within the specified distance), divided by the total number of possible joinings between all patches of the corresponding patch type, multiplied by 100 to convert to a percentage.

Units 

Percent

Range

0 ≤ CONNECT ≤ 100


CONNECT = 0 when either the focal class consists of a single patch or none of the patches of the focal class are "connected" (i.e., within the user-specified threshold distance of another patch of the same type). CONNECT = 100 when every patch of the focal class is "connected."

Comments

Connectance is defined on the number of functional joinings between patches of the corresponding patch type, where each pair of patches is either connected or not based on a user-specified distance criterion. Connectance is reported as a percentage of the maximum possible connectance given the number of patches. Note, connectance can be based on either Euclidean distance or functional distance, as described elsewhere (see Isolation/Proximity Metrics), although this is not implemented yet. Also, note that Euclidean distances are calculated from cell center to cell center. Thus, two patches that have 10 10-m cells between them have a computed distance of 110 m, not 100 m.