(P21) Functional Nearest-Neighbor Distance

h_ij^* =distance (m) from patch ij to its nearest neighboring patch of the same type (class), based on least cost path edge-to-edge distance, computed from cell center to cell center.

Description

FNN equals the distance (m) to the nearest neighboring patch of the same type, based on the least cost path edge-to-edge distance. Note that the edge-to-edge distances are from cell center to cell center.

Units 

Meters

Range

FNN > 0, without limit.

FNN approaches 0 as the distance to the nearest neighbor decreases. The minium FNN is constrained by the cell size, and is equal to twice the cell size when the 8-neighbor patch rule is used or the distance between diagonal neighbors when the 4-neighbor rule is used. The upper limit is constrained by the extent of the landscape. FNN is undefined and reported as "N/A" in the “basename”.patch file if the patch has no neighbors (i.e., no other patches of the same class).

Comments

Functional nearest-neighbor distance accounts for one of the major shortcomings of using Euclidean distance to assess ecological relationships; namely, that the shortest geographic distance may not be the shortest ecological distance as perceived by an organism or process.