Some isochrones not aligned to roads

Martijn · February 8, 2018, 2:24am

I have a GraphHopper server running on my machine using the isochrone_open_source branch. I am using OSM data from geofabrik.

Some of the isochrones have spikes that are not aligned to roads or parts going out over the ocean.

Any ideas what the cause is? Is this something I can fix by tuning GraphHopper?

Some examples of the output:

boldtrn · February 9, 2018, 12:55am

Do these spikes occur for the Directions API as well?

karussell · February 9, 2018, 8:24am

It is a known limitation of the current implementation. A workaround is to explore a larger area.

Martijn · February 11, 2018, 11:43pm

I see, thanks! How do I explore a larger area (while still getting the same isochrones)?

Martijn · February 12, 2018, 5:05am

I don’t have access to the Directions API to test.

boldtrn · February 12, 2018, 5:35am

You can always have a look at the live samples.

Martijn · February 12, 2018, 5:51am

Looks like fairly similar output from the live sample. I am using remote areas with sparse road networks. May be a bit harder for the algorithm to deal with?

(Clinton, South Australia)