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GYRATE_MN (class level)

Source: R/lsm_c_gyrate_mn.R
lsm_c_gyrate_mn.Rd

Mean radius of gyration (Area and edge metric)

Usage

lsm_c_gyrate_mn(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

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

GYRATE_MN is an 'Area and edge metric'. The metric summarises each class as the mean of the radius of gyration of all patches belonging to class i. 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_MN >= 0

Behaviour

Approaches GYRATE_MN = 0 if every patch is a single cell. Increases, without limit, when only one patch is present.

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, mean,
lsm_c_gyrate_sd, lsm_c_gyrate_cv,
lsm_l_gyrate_mn, lsm_l_gyrate_sd, lsm_l_gyrate_cv

Examples

landscape <- terra::rast(landscapemetrics::landscape)
lsm_c_gyrate_mn(landscape)
#> # A tibble: 3 × 6
#>   layer level class    id metric    value
#>   <int> <chr> <int> <int> <chr>     <dbl>
#> 1     1 class     1    NA gyrate_mn  1.40
#> 2     1 class     2    NA gyrate_mn  1.30
#> 3     1 class     3    NA gyrate_mn  3.84