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Edge Density (Area and Edge metric)

Usage

lsm_c_ed(landscape, count_boundary = FALSE, directions = 8)

Arguments

landscape

A categorical raster object: SpatRaster; Raster* Layer, Stack, Brick; stars or a list of SpatRasters.

count_boundary

Count landscape boundary as edge.

directions

The number of directions in which patches should be connected: 4 (rook's case) or 8 (queen's case).

Value

tibble

Details

$$ED = \frac{\sum \limits_{k = 1}^{m} e_{ik}} {A} * 10000$$ where \(e_{ik}\) is the total edge length in meters and \(A\) is the total landscape area in square meters.

ED is an 'Area and Edge metric'. The edge density equals the sum of all edges of class i in relation to the landscape area. The boundary of the landscape is only included in the corresponding total class edge length if count_boundary = TRUE. The metric describes the configuration of the landscape, e.g. because an aggregation of the same class will result in a low edge density. The metric is standardized to the total landscape area, and therefore comparisons among landscapes with different total areas are possible.

Units

Meters per hectare

Range

ED >= 0

Behaviour

Equals ED = 0 if only one patch is present (and the landscape boundary is not included) and increases, without limit, as the landscapes becomes more patchy

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_ed(landscape)
#> # A tibble: 3 × 6
#>   layer level class    id metric value
#>   <int> <chr> <int> <int> <chr>  <dbl>
#> 1     1 class     1    NA ed     2011.
#> 2     1 class     2    NA ed     2256.
#> 3     1 class     3    NA ed     3289.