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Mean number of disjunct core areas (Core area metric)

Usage

lsm_l_dcore_mn(
  landscape,
  directions = 8,
  consider_boundary = FALSE,
  edge_depth = 1
)

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

Value

tibble

Details

$$DCORE_{MN} = mean(NCORE[patch_{ij}])$$ where \(NCORE[patch_{ij}]\) is the number of core areas.

DCORE_MN is an 'Core area metric'. It summarises the landscape as the mean of all patches in the landscape. A cell is defined as core if the cell has no neighbour with a different value than itself (rook's case). NCORE counts the disjunct core areas, whereby a core area is a 'patch within the patch' containing only core cells.

Units

None

Range

DCORE_MN > 0

Behaviour

Equals DCORE_MN = 0 if NCORE = 0 for all patches. Increases, without limit, as the number of disjunct core areas increases.

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

Examples

landscape <- terra::rast(landscapemetrics::landscape)
lsm_l_dcore_mn(landscape)
#> # A tibble: 1 × 6
#>   layer level     class    id metric   value
#>   <int> <chr>     <int> <int> <chr>    <dbl>
#> 1     1 landscape    NA    NA dcore_mn 0.679