Unable to build isochrone map (error 3099)


Hi everyone,

I am trying to calculate isochrones around some event coordinates:

for i, event in islice(enumerate(events.itertuples()), start_from, len(events)):
event_coords = [[event.event_longitude, event.event_latitude]]

        isochrones = client.isochrones(event_coords, range_type=range_type, range=iso_ranges)
        isochrones_per_event[i] = isochrones

Unfortunately the following error code is returned:
{‘error’: {‘code’: 3099, ‘message’: ‘Unable to build an isochrone map.’}

I am unsure, however, whether this might have to do with the new API as the proposed lines of codes worked for v1, so I might just be completely missing out on something.



Hi Verena,

we need a URL, otherwise we can’t look at it. Use dry_run=True and paste the URL and parameters here.


Hi Nils,

I just realized the error overlapped with another error in my code (not fixed yet, but it is definitely not related to your API) and I falsely attributed the incorrect output to the response from the API. So sorry for my earlier post!

The API’s error code 3099 is returned for some coordinates that are too far away from any road network, which is plausible for the context I am working in. But the other coordinates work fine.