TCA (class level)
Total core area (Core area metric)
lsm_c_tca(landscape, directions = 8, consider_boundary = FALSE, edge_depth = 1)
landscape |
Raster* Layer, Stack, Brick, SpatRaster (terra), stars, or a list of rasterLayers. |
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 |
TCA = ∑_{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.
Hectares
TCA >= 0
Increases, without limit, as patch areas increase and patch shapes simplify. TCA = 0 when every cell in every patch of class i is an edge.
tibble
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
lsm_c_tca(landscape)
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