Compute distance matrix between sf objects

Computes pairwise distances between geometries. For geographic (longlat) coordinate systems, uses great circle distances in meters via sf::st_distance(). For projected coordinate systems, uses fast Euclidean distance in the CRS units (typically meters).

Usage

distance_matrix(
  x,
  y = NULL,
  type = c("euclidean", "manhattan"),
  use_centroids = NULL
)

Arguments

x

An sf object (demand points for facility location, or areas for regionalization).

y

An sf object (facility locations). If NULL, computes distances within x.

type

Distance type: "euclidean" (default) or "manhattan". Note that for geographic CRS, only "euclidean" (great circle) distance is available.

use_centroids

Logical. If TRUE (default for polygons), use polygon centroids.

Value

A numeric matrix of distances. Rows correspond to x, columns to y. For geographic CRS, distances are in meters. For projected CRS, distances are in the CRS units (usually meters).

Examples

# \donttest{
library(sf)
demand <- st_as_sf(data.frame(x = runif(10), y = runif(10)), coords = c("x", "y"))
facilities <- st_as_sf(data.frame(x = runif(5), y = runif(5)), coords = c("x", "y"))
d <- distance_matrix(demand, facilities)
# }