Build a Distance Matrix from a Custom Data Frame

Generates an all-pairs distance matrix from latitude/longitude coordinates in a user-supplied data frame. Row and column names of the matrix are set from a unique label variable.

Usage

custom_distance_matrix(
  df,
  unit = c("miles", "kilometers", "meters"),
  label_var,
  lat_var,
  long_var
)

Arguments

df

A data.frame containing label and coordinate columns.

unit

Character string; one of "miles" (default), "kilometers", or "meters".

label_var

Character scalar; column name to use for matrix row/column names. Values in this column must be unique and non-missing.

lat_var

Character scalar; column name containing latitude values.

long_var

Character scalar; column name containing longitude values.

Value

A list with:

loc_vec

Character vector of location labels (same order as matrix dimensions)

distance_matrix

Square numeric matrix of pairwise distances in requested units

Examples

# \donttest{
md <- tract_generator("24")
dm <- custom_distance_matrix(
  md,
  label_var = "geoid", lat_var = "latitude", long_var = "longitude"
)
dim(dm[["distance_matrix"]])
#> [1] 1475 1475

names(md) <- c("tract_id", "lat", "lon")
dm_km <- custom_distance_matrix(
  md,
  unit = "kilometers",
  label_var = "tract_id",
  lat_var = "lat",
  long_var = "lon"
)
# }