Standard deviation of core area index (Core area metric)
lsm_c_cai_sd(
landscape,
directions = 8,
consider_boundary = FALSE,
edge_depth = 1
)tibble
Raster* Layer, Stack, Brick, SpatRaster (terra), stars, or a list of rasterLayers.
The number of directions in which patches should be connected: 4 (rook's case) or 8 (queen's case).
Logical if cells that only neighbour the landscape boundary should be considered as core
Distance (in cells) a cell has the be away from the patch edge to be considered as core cell
$$CAI_{SD} = sd(CAI[patch_{ij}]$$ where \(CAI[patch_{ij}]\) is the core area index of each patch.
CAI_SD is a 'Core area metric'. The metric summarises each class as the standard deviation of the core area index of all patches belonging to class i. The core area index is the percentage of core area in relation to patch area. A cell is defined as core area if the cell has no neighbour with a different value than itself (rook's case). The metric describes the differences among patches of the same class i in the landscape.
Percent
CAI_SD >= 0
Equals CAI_SD = 0 if the core area index is identical for all patches. Increases, without limit, as the variation of core area indices increases.
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: https://www.umass.edu/landeco/
lsm_p_cai,
sd,
lsm_c_cai_mn,
lsm_c_cai_cv,
lsm_l_cai_mn,
lsm_l_cai_sd,
lsm_l_cai_cv