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DIVISION (landscape level)

Source: R/lsm_l_division.R
lsm_l_division.Rd

Landscape division index (Aggregation metric)

Usage

lsm_l_division(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

$$DIVISON = (1 - \sum \limits_{i = 1}^{m} \sum \limits_{j = 1}^{n} (\frac{a_{ij}} {A}) ^ 2) $$ where \(a_{ij}\) is the area in square meters and \(A\) is the total landscape area in square meters.

DIVISION is an 'Aggregation metric. It can be in as the probability that two randomly selected cells are not located in the same patch. The landscape division index is negatively correlated with the effective mesh size (lsm_c_mesh).

Units

Proportion

Ranges

0 <= Division < 1

Behaviour

Equals DIVISION = 0 if only one patch is present. Approaches DIVISION = 1 if all patches of class i are single cells.

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

Jaeger, J. A. 2000. Landscape division, splitting index, and effective mesh size: new measures of landscape fragmentation. Landscape ecology, 15(2), 115-130.

See also

lsm_p_area, lsm_l_ta,
lsm_c_division

Examples

landscape <- terra::rast(landscapemetrics::landscape)
lsm_l_division(landscape)
#> # A tibble: 1 × 6
#>   layer level     class    id metric   value
#>   <int> <chr>     <int> <int> <chr>    <dbl>
#> 1     1 landscape    NA    NA division 0.896