Euclidean distance to nearest neighbour
Details
Fast and memory safe Rcpp implementation for calculating the minimum Euclidean
distances to the nearest patch of the same class in a raster or matrix.
All patches need an unique ID (see get_patches). Please be aware
that the patch ID is not identical to the patch ID of all metric functions (lsm_).
If return_ID = TRUE, for some focal patches several nearest neighbour patches
might be returned.
Because the metric is based on distances or areas please make sure your data
is valid using check_landscape.
References
Based on RCpp code of Florian Privé florian.prive.21@gmail.com
Examples
# get patches for class 1
landscape <- terra::rast(landscapemetrics::landscape)
class_1 <- get_patches(landscape, class = 2)[[1]][[1]]
# calculate the distance between patches
get_nearestneighbour(class_1)
#> # A tibble: 13 × 3
#> layer id dist
#> <int> <dbl> <dbl>
#> 1 1 10 4.47
#> 2 1 11 5.83
#> 3 1 12 2.83
#> 4 1 13 4.12
#> 5 1 14 3
#> 6 1 15 3
#> 7 1 16 3.16
#> 8 1 17 3
#> 9 1 18 3
#> 10 1 19 2.83
#> 11 1 20 5.83
#> 12 1 21 2.83
#> 13 1 22 3
get_nearestneighbour(class_1, return_id = TRUE)
#> # A tibble: 15 × 4
#> layer id dist id_neighbour
#> <int> <dbl> <dbl> <dbl>
#> 1 1 10 4.47 14
#> 2 1 11 5.83 13
#> 3 1 12 2.83 19
#> 4 1 13 4.12 12
#> 5 1 14 3 15
#> 6 1 15 3 14
#> 7 1 16 3.16 15
#> 8 1 17 3 18
#> 9 1 18 3 12
#> 10 1 18 3 17
#> 11 1 19 2.83 12
#> 12 1 19 2.83 21
#> 13 1 20 5.83 22
#> 14 1 21 2.83 19
#> 15 1 22 3 19