lsm_l_siei() R function from [landscapemetrics]

SIEI (landscape level)

Simpson's evenness index (Diversity metric)


lsm_l_siei(landscape, directions = 8)

Arguments

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

Returns

tibble

Details

SIEI = \frac{1 - \sum \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.

Units

None

Range

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

Examples


landscape <- terra::rast(landscapemetrics::landscape)
lsm_l_siei(landscape)

References

McGarigal K., SA Cushman, and E Ene. 2023. FRAGSTATS v4: Spatial Pattern Analysis Program for Categorical Maps. Computer software program produced by the authors; available at the following web site: https://www.fragstats.org

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

lsm_l_siei function