Description

Shannons's evenness index (Diversity metric)

Usage

Arguments

Details

SHEI = \frac{- ∑ \limits_{i = 1} ^ {m} (P_{i} * \ln P_{i})} {\ln m}

where P_{i} is the proportion of class i and m is the number of classes.

SHEI is a 'Diversity metric'. It is the ratio between the actual Shannon's diversity index and and the theoretical maximum of the Shannon diversity index. It can be understood as a measure of dominance.

Units

None

Range

0 <= SHEI < 1

Behaviour

Equals SHEI = 0 when only one patch present and equals SHEI = 1 when the proportion of classes is completely equally distributed

Value

tibble

References

McGarigal, K., SA Cushman, and E Ene. 2012. FRAGSTATS v4: Spatial Pattern Analysis Program for Categorical and Continuous Maps. Computer software program produced by the authors at the University of Massachusetts, Amherst. Available at the following web site: http://www.umass.edu/landeco/research/fragstats/fragstats.html

Shannon, C., and W. Weaver. 1949. The mathematical theory of communication. Univ. IllinoisPress, Urbana

See Also

lsm_c_pland, lsm_l_pr

Examples