CORE (patch level)

Core area (Core area metric)

Usage

lsm_p_core(
  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

$$CORE = a_{ij}^{core}$$ where \(a_{ij}^{core}\) is the core area in square meters

CORE is a 'Core area metric' and equals the area within a patch that is not on the edge of it. A cell is defined as core area if the cell has no neighbour with a different value than itself (rook's case). It describes patch area and shape simultaneously (more core area when the patch is large and the shape is rather compact, i.e. a square).

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

Units

Hectares

Range

CORE >= 0

Behaviour

Increases, without limit, as the patch area increases and the patch shape simplifies (more core area). CORE = 0 when every cell in the patch is an edge.

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

See also

lsm_c_core_mn, lsm_c_core_sd, lsm_c_core_cv, lsm_c_tca,
lsm_l_core_mn, lsm_l_core_sd, lsm_l_core_cv, lsm_l_tca

Examples

landscape <- terra::rast(landscapemetrics::landscape)
lsm_p_core(landscape)
#> # A tibble: 28 × 6
#>    layer level class    id metric  value
#>    <int> <chr> <int> <int> <chr>   <dbl>
#>  1     1 patch     1     1 core   0     
#>  2     1 patch     1     2 core   0     
#>  3     1 patch     1     3 core   0.0035
#>  4     1 patch     1     4 core   0     
#>  5     1 patch     1     5 core   0     
#>  6     1 patch     1     6 core   0.0038
#>  7     1 patch     1     7 core   0.0003
#>  8     1 patch     1     8 core   0     
#>  9     1 patch     1     9 core   0     
#> 10     1 patch     2    10 core   0.0009
#> # ℹ 18 more rows