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).
consider_boundary: Logical if cells that only neighbour the landscape boundary should be considered as core
edge_depth: Distance (in cells) a cell has the be away from the patch edge to be considered as core cell
Returns
tibble
Details
CORESD=sd(CORE[patchij])
where CORE[patchij] is the core area in square meters of each patch.
CORE_SD is a 'Core area metric'. It equals the standard deviation of the core area of all patches in the landscape. The core area is defined as all cells that have no neighbour with a different value than themselves (rook's case). The metric describes the differences among all patches in the landscape.
Because the metric is based on distances or areas please make sure your data is valid using check_landscape.
Units
Hectares
Range
CORE_SD >= 0
Behaviour
Equals CORE_SD = 0 if all patches have the same core area. Increases, without limit, as the variation of patch core areas increases.
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