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Mean of patch area (Area and edge metric)

Usage

lsm_l_area_mn(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

$$AREA_{MN} = mean(AREA[patch_{ij}])$$ where \(AREA[patch_{ij}]\) is the area of each patch in hectares

AREA_MN is an 'Area and Edge metric'. The metric summarises the landscape as the mean of all patch in the landscape. The metric is a simple way to describe the composition of the landscape. Especially together with the total landscape area (lsm_l_ta), it can also give an an idea of patch structure (e.g. many small patches vs. few larges patches).

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

Units

Hectares

Range

AREA_MN > 0

Behaviour

Approaches AREA_MN = 0 if all patches are small. Increases, without limit, as the patch areas increase.

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_area_mn(landscape)
#> # A tibble: 1 × 6
#>   layer level     class    id metric    value
#>   <int> <chr>     <int> <int> <chr>     <dbl>
#> 1     1 landscape    NA    NA area_mn 0.00321