edges_weights_matrix function

Create an edges weights matrix

Creates an edges weights matrix from the output of distance_euclidean().

edges_weights_matrix(distances, lower = TRUE, upper = TRUE, diag = TRUE)

Arguments

• distances: a data.frame with the following three columns: from

  (the first node of the edge), to (the second node of the edge), and weight (the weight of the edge between the two nodes, e.g. a distance).

• lower: a logical value. If TRUE (default), keep values in the lower triangle of the matrix. Otherwise they will be replaced by NA.

• upper: a logical value. If TRUE (default), keep values in the upper triangle of the matrix. Otherwise they will be replaced by NA.

• diag: a logical value. If TRUE (default), keep values in the diagonal of the matrix. Otherwise they will be replaced by NA.

Returns

An edges weights matrix of dimensions n x n, where n is the number of nodes (sites).

Examples

# Import Adour sites ----
path_to_file <- system.file("extdata", "adour_survey_sampling.csv", 
                            package = "chessboard")
adour_sites <- read.csv(path_to_file)

# Select the 15 first sites ----
adour_sites <- adour_sites[1:15, ]

# Create node labels ----
adour_sites <- create_node_labels(adour_sites, 
                                  location = "location", 
                                  transect = "transect", 
                                  quadrat  = "quadrat")

# Convert sites to sf object (POINTS) ----
adour_sites_sf <- sf::st_as_sf(adour_sites, 
                               coords = c("longitude", "latitude"),
                               crs = "epsg:2154")

# Compute distances between pairs of sites along the Adour river ----
adour_dists <- distance_euclidean(adour_sites_sf)

# Create Edges weights matrix ----
edges_weights_matrix(adour_dists)

# Create Edges weights matrix (with options) ----
edges_weights_matrix(adour_dists, lower = FALSE)
edges_weights_matrix(adour_dists, upper = FALSE)
edges_weights_matrix(adour_dists, diag = FALSE)