DCORE_SD (class level)

Standard deviation number of disjunct core areas (Core area metric)

Usage

lsm_c_dcore_sd(
  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

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

DCORE_SD is an 'Core area metric'. It summarises each class as the standard deviation of all patch areas belonging to class i. 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. The metric describes the differences among patches of the same class i in the landscape.

Units

None

Range

DCORE_SD >= 0

Behaviour

Equals DCORE_SD = 0 if all patches have the same number of disjunct core areas. Increases, without limit, as the variation of 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_c_dcore_sd(landscape)
#> # A tibble: 3 × 6
#>   layer level class    id metric   value
#>   <int> <chr> <int> <int> <chr>    <dbl>
#> 1     1 class     1    NA dcore_sd 0.882
#> 2     1 class     2    NA dcore_sd 0.660
#> 3     1 class     3    NA dcore_sd 1.03