Isochrone returns 200 but fails to build a polygon

openrouteservice
1

If I attempt to draw an isochrone from the location -2.21, 53.04

curl -X POST   'https://api.openrouteservice.org/v2/isochrones/driving-car'  -d '{"locations":[[-2.21,53.04]],"range":[360]}' -H 'Content-Type: application/json; charset=utf-8'   -H 'Accept: application/json, application/geo+json, application/gpx+xml, img/png; charset=utf-8'

It returns 200 but draws a nonsense isochrone

If I move the isochrone location 500 metres west -2.215, 53.04

curl -X POST   'https://api.openrouteservice.org/v2/isochrones/driving-car'  -d '{"locations":[[-2.2105,53.04]],"range":[360]}' -H 'Content-Type: application/json; charset=utf-8'   -H 'Accept: application/json, application/geo+json, application/gpx+xml, img/png; charset=utf-8'

It returns 200 and draws a plausible isochrone

I have extended the limits in the ors-config.json but this does not look like I am hitting any limits.

Am I missing something?

2

Hey,

the resulting isochrone in the first place isn’t nonsene, but a product (albeit a rather strange on) of the particulars of the road network and the isochrone algorithm.

First, the point given is not on a road, so the openrouteservice snaps to the nearest, driveable road. In this case, that is a point on the highway=track of the Scott Lidgett Road Allotments.
Next, it’s trying to determine what it can reach in the given time. Since there is a barrier=gate on the “exit” of the tracks, and barriers are treated as impassable by default, the only places to go to are the three tracks on the allottments.
Then, it takes the end points of those tracks plus some interior points on roads that surpass a certain length and uses them to build an isochrone. In most cases, this is fine (especially for a 6-Minute car isochrone), but here, it produces this rather weird-looking triangle.

I hope this explains what is happening :slight_smile:
Best regards