CORE_SD (landscape level)

Standard deviation of patch core area (class level)

Usage

lsm_l_core_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

$$CORE_{SD} = sd(CORE[patch_{ij}])$$ where $CORE[patch_{ij}]$ is the core area in square meters of each patch.

CORE_SD is a 'Core area metric'. It equals the standard deviation of the core area of all patches in the landscape. The core area is defined as all cells that have no neighbour with a different value than themselves (rook's case). The metric describes the differences among all patches in the landscape.

Because the metric is based on distances or areas please make sure your data is valid using check_landscape.

Units

Hectares

Range

CORE_SD >= 0

Behaviour

Equals CORE_SD = 0 if all patches have the same core area. Increases, without limit, as the variation of patch 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_core_sd(landscape)
#> # A tibble: 1 × 6
#>   layer level     class    id metric    value
#>   <int> <chr>     <int> <int> <chr>     <dbl>
#> 1     1 landscape    NA    NA core_sd 0.00246