Skip to contents

Edge Density (Area and Edge metric)

Usage

lsm_l_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

$$ED = \frac{E} {A} * 10000$$ where \(E\) is the total landscape edge in meters and \(A\) is the total landscape area in square meters.

ED is an 'Area and Edge metric'. The edge density equals all edges in the landscape 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 overall aggregation of classes 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.

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

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_l_ed(landscape)
#> # A tibble: 1 × 6
#>   layer level     class    id metric value
#>   <int> <chr>     <int> <int> <chr>  <dbl>
#> 1     1 landscape    NA    NA ed     3778.