Matrix return NULL for French islands

I use my own openrouteservice instance (v8.0.0) to calculate a time matrix between all French municipalities (34977 municipalities). For municipalities located in mainland France (top left of the attached image), the matrix returns access time values.

But for most of the municipalities of Corsica (right of the attached image), the matrix return null values although there are many roads in this area. The strangest thing is that 4 municipalities in Corsica no returned null value !

In the image attached the green triangles are getting access time value but for the red triangles the matrix returns null.

I read the post below which seems to be talking about the same subject. So I changed the min_network_size parameter from 200 to 20 but the problem is still the same.

I also tried using the direction service between 2 municipalities in Corsica to check if there are roads in this area. The result returns a route between the two municipalities !

I use the pbf file(france-latest.osm.pbf), that I downloaded from Geofabrik Download Server.
Are there any settings that I don’t know about that would help resolve this ?

Thanks a lot for your help !


You are probably running into this issue (was in wrong category): Matrix endpoint returning null for all locations when some routes exist

Actual issue: Matrix endpoint returning null for all locations when one route does not exist · Issue #1785 · GIScience/openrouteservice · GitHub

Best regards

The problem doesn’t seem to come from a route that doesn’t exist. Indeed, I carried out a test on the specific area which causing the problem (Corsica). I calculate the matrix only between the municipalities of Corsica (I replaced france-latest.osm.pbf file with corse-latest.osm.pbf to rebuild the graph). The results returned by the matrix are those expected and do not contain any null values.

The error seems to occur when I try to calculate a matrix with destinations/sources located in mainland France and Corsica.

Best regards,