Compute a travel-time matrix from census tract representative points to source points

Builds a travel-time matrix using the r5r routing engine. Computes travel times from representative points of target census tracts to geolocated source points (e.g., polling locations).

Usage

compute_travel_times(
  tracts_sf,
  points_sf,
  network_path,
  tract_id = "id",
  point_id = "id",
  routing = routing_control(),
  verbose = TRUE
)

Arguments

tracts_sf

An sf object with polygon geometries. Target census tracts.

points_sf

An sf object with point geometries. Source points.

network_path

Character. Path to the directory containing the OSM .pbf file for building the r5r network.

tract_id

Character. Name of the ID column in tracts_sf. Default: "id".

point_id

Character. Name of the ID column in points_sf. Default: "id".

routing

A routing_control() object with routing parameters (mode, point_method, max_trip_duration, n_threads, gtfs_zip_path, departure_datetime, pop_raster, min_area_for_pop_weight, osm_buffer_km, fill_missing). Default: routing_control().

verbose

Logical. Default: TRUE.

Value

A numeric matrix [n_tracts x n_points]. Travel times in minutes. Row names = census tract IDs, column names = point IDs. Unreachable pairs are filled with fill_missing.

Details

Requires the r5r and sf packages. r5r requires exactly Java/JDK 21. Use download_r5r_data() to obtain the OSM data needed for network_path.

See also

routing_control() for routing parameters, download_r5r_data() to download OSM and elevation data.

Other spatial: download_r5r_data()

Examples

if (FALSE) { # \dontrun{
tt <- compute_travel_times(
  tracts_sf = tracts, points_sf = stations,
  network_path = "path/to/osm_data",
  tract_id = "code_tract", point_id = "id"
)

# Transit mode with GTFS
tt <- compute_travel_times(
  tracts_sf = tracts, points_sf = stations,
  network_path = "path/to/osm_data",
  routing = routing_control(
    mode = c("WALK", "TRANSIT"),
    gtfs_zip_path = "sptrans.zip",
    departure_datetime = as.POSIXct("2022-10-02 10:00:00")
  )
)
} # }