Geographic distance between sites

Calculate pairwise geographic distances between occupied sites in a phylospatial object. The result is a dist object with the same dimensions and site ordering as ps_dissim(), making it straightforward to compare phylogenetic dissimilarity with geographic distance (e.g., for distance-decay analyses or Mantel tests).

Usage

ps_geodist(ps)

Arguments

ps

A phylospatial object with spatial data.

Value

A pairwise geographic distance matrix of class dist, with one entry per pair of occupied sites. Units are meters when a CRS is defined, or raw coordinate units otherwise.

Details

For raster data, distances are computed between cell centroids. For polygon or line sf data, distances are computed between geometry centroids. Great-circle distances are used automatically when the data has a geographic (lon/lat) CRS; Euclidean distances are used for projected data or data without a CRS. Units are meters when a CRS is defined, or unitless coordinate distances otherwise.

Examples

# \donttest{
ps <- moss()
geo <- ps_geodist(ps)
phy <- ps_dissim(ps)

# distance-decay plot
plot(as.vector(geo), as.vector(phy),
     xlab = "Geographic distance (m)",
     ylab = "Phylogenetic dissimilarity",
     pch = ".", col = "#00000020")

# }