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
Details
$$CORE_{MN} = mean(CORE[patch_{ij}])$$
where \(CORE[patch_{ij}]\) is the core area in square meters of each patch.
CORE_MN is a 'Core area metric' and equals the mean of core areas of all patches
belonging to class i. The core area is defined as all cells that have no
neighbour with a different value than themselves (rook's case).
Because the metric is based on distances or areas please make sure your data
is valid using check_landscape.
Units
Hectares
Range
CORE_MN >= 0
Behaviour
Equals CORE_MN = 0 if CORE = 0 for all patches. Increases,
without limit, as the core area indices increase.
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