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GYRATE_SD (landscape level)

Source: R/lsm_l_gyrate_sd.R
lsm_l_gyrate_sd.Rd

Standard deviation radius of gyration (Area and edge metric)

Usage

lsm_l_gyrate_sd(landscape, directions = 8, cell_center = FALSE)

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).

cell_center

If true, the coordinates of the centroid are forced to be a cell center within the patch.

Value

tibble

Details

$$GYRATE_{SD} = sd(GYRATE[patch_{ij}])$$ where \(GYRATE[patch_{ij}]\) equals the radius of gyration of each patch.

GYRATE_SD is an 'Area and edge metric'. The metric summarises the landscape as the standard deviation of the radius of gyration of all patches in the landscape. GYRATE measures the distance from each cell to the patch centroid and is based on cell center-to-cell center distances. The metrics characterises both the patch area and compactness.

If cell_center = TRUE some patches might have several possible cell-center centroids. In this case, the gyrate index is based on the mean distance of all cells to all possible cell-center centroids.

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

Units

Meters

Range

GYRATE_SD >= 0

Behaviour

Equals GYRATE_SD = 0 if the radius of gyration is identical for all patches. Increases, without limit, as the variation of the radius of gyration 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

Keitt, T. H., Urban, D. L., & Milne, B. T. 1997. Detecting critical scales in fragmented landscapes. Conservation ecology, 1(1).

See also

lsm_p_gyrate,
lsm_c_gyrate_mn, lsm_c_gyrate_sd, lsm_c_gyrate_cv,
lsm_l_gyrate_mn, lsm_l_gyrate_cv

Examples

landscape <- terra::rast(landscapemetrics::landscape)
lsm_l_gyrate_sd(landscape)
#> # A tibble: 1 × 6
#>   layer level     class    id metric    value
#>   <int> <chr>     <int> <int> <chr>     <dbl>
#> 1     1 landscape    NA    NA gyrate_sd  1.87