Patch density (Aggregation metric)
Usage
lsm_c_pd(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
$$PD = \frac{n_{i}} {A} * 10000 * 100$$
where \(n_{i}\) is the number of patches and \(A\) is the total landscape
area in square meters.
PD is an 'Aggregation metric'. It describes the fragmentation of a class, however, does not
necessarily contain information about the configuration or composition of the class. In
contrast to lsm_c_np it is standardized to the area and comparisons among
landscapes with different total area are possible.
Because the metric is based on distances or areas please make sure your data
is valid using check_landscape.
Units
Number per 100 hectares
Behaviour
Increases as the landscape gets more patchy. Reaches its maximum
if every cell is a different patch.
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
Examples
landscape <- terra::rast(landscapemetrics::landscape)
lsm_c_pd(landscape)
#> # A tibble: 3 × 6
#> layer level class id metric value
#> <int> <chr> <int> <int> <chr> <dbl>
#> 1 1 class 1 NA pd 10000
#> 2 1 class 2 NA pd 14444.
#> 3 1 class 3 NA pd 6667.
