Local clustering using DTSCAN

Within each existing .putative_cluster region (typically produced by slice_ctdf()), run sf_dtscan() on the points in that region to split it into one or more local spatial subclusters. The resulting labels are combined with the parent .putative_cluster id and written back to .putative_cluster in-place.

Usage

local_cluster_ctdf(ctdf, nmin = 3, area_z_min = 0, length_z_min = 0)

Arguments

ctdf

A ctdf object.

nmin

Integer; passed as min_pts to sf_dtscan() when clustering within each .putative_cluster region.

area_z_min

Numeric; passed to sf_dtscan() as area_z_min.

length_z_min

Numeric; passed to sf_dtscan() as length_z_min.

Value

The input ctdf, invisibly, with .putative_cluster updated in-place.

See also

sf_dtscan()

Examples

data(mini_ruff)
x = as_ctdf(mini_ruff)
x = x[.id < 20][, .putative_cluster := 1]
local_cluster_ctdf(x)
#> <ctdf: 19 locations>
#> 
#>               timestamp                location   .id
#>                  <POSc>             <sfc_POINT> <int>
#>  1: 2015-05-31 14:33:09 POINT (2768520 7462407)     1
#>  2: 2015-05-31 15:12:44 POINT (2754196 7461678)     2
#>  3: 2015-05-31 16:41:01 POINT (2750888 7456491)     3
#> ---                                                  
#> 17: 2015-06-01 04:14:45 POINT (2717859 7445205)    17
#> 18: 2015-06-01 04:45:02 POINT (2722075 7445131)    18
#> 19: 2015-06-01 05:06:36 POINT (2819856 7454370)    19
x
#> <ctdf: 19 locations>
#> 
#>               timestamp                location   .id
#>                  <POSc>             <sfc_POINT> <int>
#>  1: 2015-05-31 14:33:09 POINT (2768520 7462407)     1
#>  2: 2015-05-31 15:12:44 POINT (2754196 7461678)     2
#>  3: 2015-05-31 16:41:01 POINT (2750888 7456491)     3
#> ---                                                  
#> 17: 2015-06-01 04:14:45 POINT (2717859 7445205)    17
#> 18: 2015-06-01 04:45:02 POINT (2722075 7445131)    18
#> 19: 2015-06-01 05:06:36 POINT (2819856 7454370)    19