AREA (patch level)

Patch area (Area and edge metric)

Usage

lsm_p_area(landscape, directions = 8)

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).

Value

tibble

Details

$$AREA = a_{ij} * (\frac{1} {10000})$$ where \(a_{ij}\) is the area in square meters.

AREA is an 'Area and edge metric' and equals the area of each patch in hectares. The lower limit of AREA is limited by the resolution of the input raster, i.e. AREA can't be smaller than the resolution squared (in hectares). It is one of the most basic, but also most important metrics, to characterise a landscape. The metric is the simplest measure of composition.

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

Units

Hectares

Range

AREA > 0

Behaviour

Increases, without limit, as the patch size 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

See also

lsm_c_area_mn, lsm_c_area_sd, lsm_c_area_cv, lsm_c_ca,
lsm_l_area_mn, lsm_l_area_sd, lsm_l_area_cv, lsm_l_ta

Examples

landscape <- terra::rast(landscapemetrics::landscape)
lsm_p_area(landscape)
#> # A tibble: 28 × 6
#>    layer level class    id metric  value
#>    <int> <chr> <int> <int> <chr>   <dbl>
#>  1     1 patch     1     1 area   0.0001
#>  2     1 patch     1     2 area   0.0005
#>  3     1 patch     1     3 area   0.0072
#>  4     1 patch     1     4 area   0.0001
#>  5     1 patch     1     5 area   0.0001
#>  6     1 patch     1     6 area   0.008 
#>  7     1 patch     1     7 area   0.0016
#>  8     1 patch     1     8 area   0.0003
#>  9     1 patch     1     9 area   0.0005
#> 10     1 patch     2    10 area   0.0034
#> # ℹ 18 more rows