ddist: Create dyads of points i and j and calculate distances

In jvieroe/dyadicdist: Compute Dyadic Distances

Description

This function calculates the geodesic distance between any dyads (pairs of points) and stores the result in a long tibble, a opposed to a wide matrix.

Usage

ddist(
  data = NULL,
  id = NULL,
  longitude = "longitude",
  latitude = "latitude",
  crs = 4326,
  crs_transform = FALSE,
  new_crs = NULL,
  diagonal = TRUE,
  duplicates = TRUE
)

Arguments

data	an object of class data.frame or tibble.
id	a variable uniquely identifying geospatial points. Can be of type numeric, integer, character, or factor
longitude	name of the numeric longitude variable. Defaults to "longitude"
latitude	name of the numeric latitude variable. Defaults to "latitude"
crs	a valid EPSG for a valid Coordinate Reference System (CRS) for your coordinates. Defaults to 4326.
crs_transform	a logical value indicating whether to transform the CRS. Defaults to FALSE
new_crs	a valid EPSG for a new CRS. See rgdal::make_EPSG() or https://epsg.org/home.html
diagonal	a logical value. Keep the diagonal component in the distance matrix with dyads (i,i) and distance zero? Defaults to TRUE
duplicates	a logical value. Keep "identical" dyads (i,j) and (j,i)? Defaults to TRUE. If set to FALSE, only one observation per dyad is kept. Note that this uses rowwise and makes the ddist function considerably more time-consuming

Value

a long tibble with dyads and dyadic distances incl. a distance unit indicator

Author(s)

Jeppe Vierø

Examples

library(tibble)
df <- tibble::tribble(
~city_name, ~idvar, ~latitude, ~longitude,
"copenhagen", 5, 55.68, 12.58,
"stockholm", 2, 59.33, 18.07,
"oslo", 51, 59.91, 10.75
)
ddist(data = df, id = "idvar")

jvieroe/dyadicdist documentation built on Jan. 21, 2022, 8:43 a.m.