lsm_l_siei {landscapemetrics} | R Documentation |
SIEI (landscape level)
Description
Simpson's evenness index (Diversity metric)
Usage
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). |
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
Value
tibble
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
See Also
Examples
landscape <- terra::rast(landscapemetrics::landscape)
lsm_l_siei(landscape)