nLSI (class level)

Normalized landscape shape index (Aggregation metric)

Usage

lsm_c_nlsi(landscape)

Arguments

landscape: A categorical raster object: SpatRaster; Raster* Layer, Stack, Brick; stars or a list of SpatRasters.

Value

tibble

Details

$$nLSI = \frac{e_{i} - \min e_{i}} {\max e_{i} - \min e_{i}}$$ where $e_{i}$ is the total edge length in cell surfaces and $\min e_{i}$ $\max e_{i}$ are the minimum and maximum total edge length in cell surfaces, respectively.

nLSI is an 'Aggregation metric'. It is closely related to the lsm_c_lsi and describes the ratio of the actual edge length of class i in relation to the hypothetical range of possible edge lengths of class i (min/max).

Currently, nLSI ignores all background cells when calculating the minimum and maximum total edge length. Also, a correct calculation of the minimum and maximum total edge length is currently only possible for rectangular landscapes.

Units

None

Ranges

0 <= nlsi <= 1

Behaviour

Equals nLSI = 0 when only one squared patch is present. nLSI increases the more disaggregated patches are and equals nLSI = 1 for a maximal disaggregated (i.e. a "checkerboard pattern").

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.

Examples

landscape <- terra::rast(landscapemetrics::landscape)
lsm_c_nlsi(landscape)
#> # A tibble: 3 × 6
#>   layer level class    id metric value
#>   <int> <chr> <int> <int> <chr>  <dbl>
#> 1     1 class     1    NA nlsi   0.203
#> 2     1 class     2    NA nlsi   0.204
#> 3     1 class     3    NA nlsi   0.169