Explained
What an isochrone map shows.
Last updated: 25 September 2026
A circle around a point says nothing about what you can reach from there. An isochrone map does: it shows the area you can actually cover in a given time on foot, by bike or by bus and train. This page explains how it is made, what to do with it and where its limits are.
What is an isochrone?
Isochrone means “equal time”: the line on which every point takes the same time to reach from a start. Everything inside that line is reachable within the chosen time, everything outside is not. The difference to a circle on the map is the difference between a straight line and a path: a lake, a river without a bridge, a mountain flank or a bus route that runs every two hours all reshape the area. That is exactly why it is honest.
How is it computed?
On foot, by bike and by car, a routing service (Valhalla) computes on the OpenStreetMap road and path network, which pixelpoint builds into routing tiles and updates itself: from a start point it searches every path within the time budget and returns the boundary of that set as an area. The reach appears as a time grid from green (close) to red (just about reachable); until it has been calculated, the map shows the area in a single colour. By bus and train, a timetable service (MOTIS) does the work: it finds every stop reachable within the budget, along with the time left at each one. Around each of these stops the map draws the walk that is still possible with the remaining time — so the transit area is the sum of these walks, shown as a travel-time field. The time budget runs from five to sixty minutes in steps of five; the start is any point on the map, by tap, by pin, by search or by link.
What guests do with it
The question guests ask is rarely “how far” but “how long”: what can I do in half an hour without a car? The map answers with an area instead of a list. The guest picks a point — the accommodation, the station, the spot they are standing on —, a mode of transport and a time budget. The area appears, and the map counts how many places lie inside it. A tap on the number opens the list of exactly these places, filtered by reachability. Bus and train are always computed from now, with the next departure; anyone who needs a different departure plans it via the route.
What destinations do with it
For a destination the same area is a planning tool. It shows which places to visit can be reached from the station without a car — and which cannot. It makes visible where the timetable leaves gaps, before a guest finds them. And it gives a claim like “reachable without a car” a basis you can show instead of assert.
Limits
The area is a model, not a timetable: it works with the usual speeds on the network, not with today's traffic, and it knows neither opening hours nor real time. New roads and paths only come in with the next network build. The transit area is a representation: nobody gets to the space between two stops, even where the area is coloured. And an isochrone map is only as good as the data beneath it — where timetable data is missing, the bus-and-train mode is missing; the map says so instead of inventing a reach.
Try it
In the demo you can draw the reach from any point.