ox_isochrone: Compute isochrones (service areas)

In osmnxr: Download, Model and Analyze 'OpenStreetMap' Street Networks

Compute isochrones (service areas)

Description

For one or more origin nodes, finds the set of nodes reachable within each cutoff (by the chosen edge weight — distance or, with ox_add_edge_travel_times(), travel time) and returns a polygon per cutoff: the hull of the reachable nodes. With several origins, reachability is the minimum cost from any origin.

Usage

ox_isochrone(g, center, cutoffs, weight = "length", ratio = 0.4)

Arguments

g	An osm_graph.
center	One or more origin node osmids (see ox_nearest_nodes()).
cutoffs	Numeric vector of cutoff values, in the units of weight.
weight	Edge column used as cost. Default "length".
ratio	Concavity for sf::st_concave_hull() (0 = most concave, 1 = convex). Default 0.4.

Details

Reachable sets come from the Rust Dijkstra core; the hull is built with sf::st_concave_hull() when available (GEOS >= 3.11), falling back to a convex hull. For metric cutoffs, project the graph to a metric CRS first.

Value

An sf object with one polygon row per cutoff (columns cutoff, n_nodes, geometry), ordered from largest to smallest cutoff so smaller areas draw on top.

Examples

g <- example_osm_graph(n = 6, spacing = 100)
center <- ox_nearest_nodes(g, 250, 250)
iso <- ox_isochrone(g, center, cutoffs = c(100, 300))
iso

osmnxr documentation built on Oct. 20, 2026, 1:07 a.m.