Simpson's evenness index (Diversity metric)
lsm_l_siei(landscape, directions)# S3 method for RasterLayer
lsm_l_siei(landscape, directions = 8)
# S3 method for RasterStack
lsm_l_siei(landscape, directions = 8)
# S3 method for RasterBrick
lsm_l_siei(landscape, directions = 8)
# S3 method for stars
lsm_l_siei(landscape, directions = 8)
# S3 method for list
lsm_l_siei(landscape, directions = 8)
Raster* Layer, Stack, Brick or a list of rasterLayers.
The number of directions in which patches should be connected: 4 (rook's case) or 8 (queen's case).
tibble
$$SIEI = \frac{1 - \sum \limits_{i = 1}^{m} P_{i}^{2}} {1 - \frac{1} {m}}$$ 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.
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
# NOT RUN {
lsm_l_siei(landscape)
# }
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