I recently took a trip from Bucharest to Craiova and back and used OsmAnd to guide me.
Roughly half way I stopped at a gas station at the southern end of Pitesti.
I was at the OMV gas station (mid-lower-right here https://www.openstreetmap.org/#map=18/44.82571/24.91486 ). As I exited the gas station through the western exting, the natural way to proceed towards Craiova would be to go north, enter the roundabout and exit through the second exit, westwards.
(green line in attached snapshot)
OsmAnd routed me towards the main road SE, make a U-turn and then proceed through the roundabout. This was completely wrong.
(red line in attached snapshot).
I made a screenshot of the details of how the ways are drawn for this place on openstreetmap.org (I’ve edited some features before), but I won’t make changes without asking first.
Is this a map issue or a OsmAnd routing algorithm issue?
Why did OsmAnd route me along the red path instead of green here?
If it’s an OsmAnd problem, IMO it should be fixed. (OsmAnd support contacted)
If it’s a map issue, how to best fix it?
There doesn’t seem to be a problem now. Maybe a problem existed when the map for that area was created. You should check if there is an update for the map available in OSMAnd and if not check again next month.
That said: I have seen OSMAnd take strange routes or detours that could not be explained by the map data and reporting this never resulted in a message like “yes, the algorithm is wrong, we will fix it”.
I’ve done some hobby development with OSM, and it was really hard to use. Also, if your app is going to generate a lot of queries, you’ll have to run your own servers, or buy service from someone who does.
I know why. Osmand is preferring the higher tier highway instead of the shorter path.
This will also manifest at a T junction with a traffic light, where the bottom of the T is the lower tier highway (assuming there are highway links going down the T). If you try to go from left to right (or vice versa), the router will make you go down the highway link, then up the other link just to bypass the traffic light at the junction.
this is why I disagree with the standard that highway link should always be set the higher tier highway that it connects to. Used to be IIRC, the highway links are decided by the condition of the link (width, etc), but then they changed. But water under the bridge now…