Wavefront Expansion Accumulation

Accumulate species within an expanding radius from seed points. Models invasion spread from introduction points.

Usage

wavefront(
  x,
  coords,
  n_seeds = 50L,
  r0 = 0,
  dr = NULL,
  n_steps = 50L,
  distance = c("euclidean", "haversine"),
  progress = TRUE,
  seed = NULL
)

Arguments

x

A site-by-species matrix.

coords

A data.frame with x and y columns, or a spacc_dist object.

n_seeds

Integer. Number of random starting points.

r0

Numeric. Initial radius. Default 0.

dr

Numeric. Radius increment per step. Default auto-calculated.

n_steps

Integer. Number of expansion steps. Default 50.

distance

Character. Distance method.

progress

Logical. Show progress?

seed

Integer. Random seed.

Value

An object of class spacc_wavefront containing:

curves

Matrix of species counts (n_seeds x n_steps)

radius

Vector of radius values

sites_included

Matrix of sites included at each step

References

Shigesada, N. & Kawasaki, K. (1997). Biological Invasions: Theory and Practice. Oxford University Press.

Examples

# \donttest{
coords <- data.frame(x = runif(50), y = runif(50))
species <- matrix(rbinom(50 * 30, 1, 0.3), nrow = 50)
wf <- wavefront(species, coords, n_seeds = 20, n_steps = 50)
plot(wf)
# }