some help from osmand site
Please Login or Register to see the links
Route calculation is slow
Please be aware that there are 2 offline routing engines in the app: a Java based approach and a "Native" (C++) routing. The Java based approach is used in 'Safe Mode', it is 10 times slower than native mode and it has strict memory limitations. If you experience it and you see messages 'Not enough memory to compute', please go to Settings -'General' - 'Safe mode' and make sure the option is disabled.
For native routing there are different limitations for different phones, depending on memory & processor. In general, native routing should handle < 300 km routes nicely. The route calculation should take between 15 sec and 4 minutes. It is prudent to not wait much longer than 4 minutes, because most likely the program will crash.
The only known workaround to compute long routes is to insert waypoints. Two additional waypoints should be enough even for very long routes.
How to calculate routes longer than 250km?
Many long routes (> 200-250km) cannot not be calculated by OsmAnd's offline routing engine today. If the app does not show a route after 7-8 minutes of calculation time, consider placing waypoints (pick e.g. places on motorways). 3-4 waypoints will be enough to calculate even 1000km routes.