lsm_p_circle {landscapemetrics} | R Documentation |
CIRCLE (patch level)
Description
Related Circumscribing Circle (Shape metric)
Usage
lsm_p_circle(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). |
Details
CIRCLE = 1 - (\frac{a_{ij}} {a_{ij}^{circle}})
where a_{ij}
is the area in square meters and a_{ij}^{circle}
the area of
the smallest circumscribing circle.
CIRCLE is a 'Shape metric'. The metric is the ratio between the patch area and the smallest circumscribing circle of the patch. The diameter of the smallest circumscribing circle is the 'diameter' of the patch connecting the opposing corner points of the two cells that are the furthest away from each other. The metric characterises the compactness of the patch and is comparable among patches with different area.
Because the metric is based on distances or areas please make sure your data
is valid using check_landscape
.
Units
None
Range
0 <= CIRCLE < 1
Behaviour
CIRCLE = 0 for a circular patch and approaches CIRCLE = 1 for a linear patch.
Value
tibble
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
Baker, W. L., and Y. Cai. 1992. The r.le programs for multiscale analysis of landscape structure using the GRASS geographical information system. Landscape Ecology 7: 291-302.
Based on C++ code from Project Nayuki (https://www.nayuki.io/page/smallest-enclosing-circle).
See Also
lsm_p_area
,
lsm_c_circle_mn
,
lsm_c_circle_sd
,
lsm_c_circle_cv
,
lsm_l_circle_mn
,
lsm_l_circle_sd
,
lsm_l_circle_cv
Examples
landscape <- terra::rast(landscapemetrics::landscape)
lsm_p_circle(landscape)