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.

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

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