Generate a travel time map

traveltime() generates a travel time map based on the input facilities, bounding box area, and travel mode.

See the friction() function for details on how the friction layer is generated.

Usage

traveltime(
  facilities,
  bb_area,
  mode = "walk",
  dowscaling_model_type = "lm",
  res_output = 100,
  cache = FALSE,
  file = NULL
)

Arguments

facilities

A sf object with the existing facilities.

bb_area

A sf boundary box object with the area of interest.

mode

(optional) A character string indicating the mode of transport. Options are "fastest" and "walk" (default = "walk").

• For "fastest": The friction layer accounts for multiple modes of transport, including walking, cycling, driving, and public transport, and are based on the Malaria Atlas Project (2019) Global Travel Speed Friction Surface.

• For "walk": The friction layer accounts only for walking speeds and is based on the Malaria Atlas Project (2015) Global Walking Only Friction Surface.

dowscaling_model_type

(optional) A character string indicating the type of model used for the spatial downscaling of the friction layer. Options are "lm" (linear model) and "rf" (random forest) (default: "lm").

res_output

(optional) A positive integerish number indicating the spatial resolution of the friction raster (and of the analysis), in meters. If the resolution is less than 1000, a spatial downscaling approach is used (default: 100).

cache

(optional) A logical flag indicating whether to cache the downloaded friction data for future use (default: TRUE).

file

(optional) A character string indicating the path to a local friction surface raster file. If provided, the function will use this file instead of downloading the friction data.

Value

An invisible list with the following elements:

• travel_time: A RasterLayer object with the travel time map.

• friction: A list with the outputs of the friction() function.

See also

Other travel time functions: friction(), traveltime_plot(), traveltime_stats()

Examples

if (FALSE) { # \dontrun{
  library(dplyr)

  traveltime_data <-
    naples_fountains |>
    traveltime(
      bb_area = naples_shape,
      dowscaling_model_type = "lm",
      mode = "walk",
      res_output = 100
    )

  traveltime_data |> glimpse()

  traveltime_data |>
    traveltime_plot(
      bb_area = naples_shape,
      facilities = naples_fountains
  )
} # }