isochronous/isodistance calculations

Calculates isochrones or isodistances in France from an sf object using the IGN API on the Géoportail platform. The reference data comes from the IGN BD TOPO® database. For further information see IGN documentation.

Usage

get_iso(x,
        value,
        type = "time",
        profile = "pedestrian",
        time_unit = "minute",
        distance_unit = "meter",
        direction = "departure",
        source = "iso",
        constraints = NULL)

get_isodistance(x,
                dist,
                unit = "meter",
                source = "iso",
                profile = "car",
                direction = "departure",
                constraints = NULL)

get_isochrone(x,
              time,
              unit = "minute",
              source = "iso",
              profile = "car",
              direction = "departure",
              constraints = NULL)

Arguments

x: Object of class sf or sfc with POINT geometry. There may be several points in the object. In this case, the output will contain as many polygons as points.
value: numeric; A quantity of time or distance.
type: character; Specifies the type of calculation performed: "time" for isochrone or "distance" for isodistance (isochrone by default).
profile: character; Type of cost used for calculation: "pedestrian" for #' pedestrians and "car" for cars. and "car" for cars ("pedestrian" by default).
time_unit: character; Allows you to specify the unit in which times are expressed in the answer: "hour", "minute" or "second" (minutes by default).
distance_unit: character; Allows you to specify the unit in which distances are expressed in the answer: "meter" or "kilometer" (meter by default).
direction: character; Direction of travel. Either define a "departure" point and obtain the potential arrival points. Or define an "arrival" point and obtain the potential points ("departure" by default).
source: character; This parameter specifies which source will be used for the calculation. Currently, "iso" and "pgr" sources are available (default "iso"). See section SOURCE for further information.
constraints: Used to express constraints on the characteristics to calculate isochrones/isodistances. See section CONSTRAINTS.
dist: numeric; A quantity of time.
unit: see time_unit and distance_unit param.
time: numeric; A quantity of time.

Value

object of class sf with POLYGON geometry

Functions

get_isodistance(): Wrapper function to calculate isodistance from get_iso.
get_isochrone(): Wrapper function to calculate isochrone from get_iso.

SOURCE

Isochrones are calculated using the same resources as for route calculation. PGR" and "ISO" resources are used, namely "bdtopo-iso" and "bdtopo-pgr".

bdtopo-pgr" is based solely on the new engine, but lacks performance on large isochrones. On the other hand, it is functional for small isochrones.
bdtopo-iso" is based on the old services over a certain distance, to solve performance problems. We recommend its use for large isochrones.