# lsm_l_siei: SIEI (landscape level) In landscapemetrics: Landscape Metrics for Categorical Map Patterns

## Description

Simpson's evenness index (Diversity metric)

## Usage

 1 lsm_l_siei(landscape, directions = 8) 

## Arguments

 landscape Raster* Layer, Stack, Brick, SpatRaster (terra), stars, or a list of rasterLayers. directions The number of directions in which patches should be connected: 4 (rook's case) or 8 (queen's case).

## Details

SIEI = \frac{1 - ∑ \limits_{i = 1}^{m} P_{i}^{2}} {1 - \frac{1} {m}}

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

SIEI is a 'Diversity metric'. The metric is widely used in biodiversity and ecology. It is the ratio between the actual Simpson's diversity index and the theoretical maximum Simpson's diversity index.

None

0 < SIEI <= 1

#### Behaviour

Equals SIEI = 0 when only one patch is present and approaches SIEI = 1 when the number of class types increases while the proportions are equally distributed

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

Simpson, E. H. 1949. Measurement of diversity. Nature 163:688

lsm_c_pland, lsm_l_pr
 1 lsm_l_siei(landscape)