ni = number of patches in the landscape of patch type (class) i.
Description NP equals the number of patches of the corresponding patch type (class).
Units None
Range NP ≥ 1, without limit.
NP = 1 when the landscape contains only one patch of the corresponding patch type; that is, when the class consists of a single patch.
Comments Number of patches of a particular patch type is a simple measure of the extent of subdivision or fragmentation of the patch type. Although the number of patches in a class may be fundamentally important to a number of ecological processes, often it has limited interpretive value by itself because it conveys no information about area, distribution, or density of patches. Of course, if total landscape area and class area are held constant, then number of patches conveys the same information as patch density or mean patch size and may be a useful index to interpret. Number of patches is probably most valuable, however, as the basis for computing other, more interpretable, metrics. Note that the choice of the 4-neighbor or 8-neighbor rule for delineating patches will have an impact on this metric.