Total core area (Core area metric)
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).
- 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
$$TCA = \sum_{j = 1}^{n} a_{ij}^{core} * (\frac{1} {10000})$$ where here \(a_{ij}^{core}\) is the core area in square meters.
TCA is a 'Core area metric' and equals the sum of core areas of all patches belonging to class i. A cell is defined as core area if the cell has no neighbour with a different value than itself (rook's case). In other words, the core area of a patch is all area that is not an edge. It characterises patch areas and shapes of patches belonging to class i simultaneously (more core area when the patch is large and the shape is rather compact, i.e. a square). Additionally, TCA is a measure for the configuration of the landscape, because the sum of edges increase as patches are less aggregated.
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