lsm_p_shape() R function from [landscapemetrics]

SHAPE (patch level)

Shape index (Shape metric)


lsm_p_shape(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).

Returns

tibble

Details

SHAPE = \frac{0.25 * p_{ij}} {\sqrt a_{ij}}

where $p_{ij}$ is the perimeter (m) and $a_{ij}$ is the area (m2).

SHAPE is a 'Shape metric'. It describes the ratio between the actual perimeter of the patch and the square root of patch area and thus adjusting for a square standard. Thus, it is a simple measure of shape complexity.

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

Units

None

Range

SHAPE >= 1

Behaviour

Equals SHAPE = 1 for a squared patch and increases, without limit, as the patch shape becomes more complex.

Examples


landscape <- terra::rast(landscapemetrics::landscape)
lsm_p_shape(landscape)

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

Patton, D. R. 1975. A diversity index for quantifying habitat "edge". Wildl. Soc.Bull. 3:171-173.

lsm_p_shape function