Draw alpha convex hull around lydemapr established points

The function takes SLF occurrence data and creates a boundary that defines their invaded range in the US.

alphahull_sf(
  data = lyde,
  alpha = 19746.64,
  bio_year = NULL,
  use_public = FALSE,
  only_established = TRUE,
  buffer_width = 10
)

Arguments

data

Unless otherwise specified, lydemapr::lyde

alpha

The coarseness of the hull drawing. Recommended value is based on cross validation work

bio_year

A double limiting lyde observations to on or before the biological year specified.

use_public

A logical specifying whether public reports should be included (FALSE by default).

only_established

A logical specifying whether only points with established SLF should be included (TRUE by default).

buffer_width

A necessary parameter for the construction of a shape from the hull (10 m recommended, so that is the default).

Value

An sf object containing the alpha convex hull polygon.

Details

From the work of: Keller J, Bona SD, Helmus MR. 2026. Leveraging spatial scale and temporal variation to track the spread rate of invasive spotted lanternflies (Lycorma delicatula). NeoBiota. 106:287–307. https://doi.org/10.3897/neobiota.106.177041

Examples

if (FALSE) { # \dontrun{

outres <- alphahull_sf(data = lyde,
                       alpha = 12000,
                       bio_year = 2025,
                       use_public = FALSE,
                       only_established = TRUE,
                       buffer_width = 10)

} # }