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Compare alternative travel routes using pollutant concentrations

alternative_trajectories.Rd

Retrieves alternative routes between an origin and a destination using the TomTom Routing API and estimates the pollutant exposure associated with each route by intersecting the trajectories with hourly pollutant concentration grids.

Usage

alternative_trajectories(
  origin,
  dest,
  mode,
  dir,
  key,
  output,
  hours = NULL,
  gridID,
  shapeValue,
  units,
  pollutant
)

Arguments

origin

Character string containing the origin coordinates in the format "latitude,longitude".

dest

Character string containing the destination coordinates in the format "latitude,longitude".

mode

Character. Travel mode accepted by the TomTom Routing API (e.g., "car", "truck", "pedestrian").

dir

Character. Directory containing the hourly pollutant grid shapefiles.

key

Character. TomTom API key.

output

Character. Output type. Either "df" to return a data frame or "plot" to return an interactive leaflet map.

hours

Character. Departure date and time in the format "YYYY-mm-dd HH:MM:SS".

gridID

Character. Name of the grid identifier field.

shapeValue

Character. Name of the pollutant concentration field in the grid.

units

Character. Units of the pollutant concentration (e.g., "µg/m³").

pollutant

Character. Pollutant name used for map labels and legends.

Value

If output = "df", a data frame summarizing the selected alternative routes and their associated travel metrics, pollutant concentrations and exposure estimates.

If output = "plot", an interactive leaflet map displaying the pollutant grid together with the selected alternative routes.

Details

The function identifies the fastest, shortest, least polluted, most polluted, lowest exposure, and highest exposure routes. Results can be returned either as a data frame or as an interactive map.

This function combines route information obtained from the TomTom Routing API with hourly pollutant concentration grids. If the trip spans multiple hourly grids, pollutant concentrations are averaged using temporary_grid_search(). Exposure is estimated as the product of the average pollutant concentration along each route and the travel time.

A valid TomTom API key and an active internet connection are required.

Examples

if (FALSE) { # \dontrun{
routes <- alternative_trajectories(
  origin = "-31.4201,-64.1888",
  dest = "-31.4300,-64.2000",
  mode = "car",
  hours = "2019-08-01 08:00:00",
  key = "YOUR_API_KEY",
  dir = "path/to/grids",
  gridID = "ID",
  shapeValue = "PM25",
  pollutant = "PM2.5",
  units = "µg/m³",
  output = "df"
)
} # }