Re-entering expressway wants me to backtrack

[David Remelts]

Say I am following a north-bound route on the expressway and I stop at a rest area and then exit the rest area to continue along the route.  Obviously, I am rejoining the original route at a point further north than where I left it when I entered the rest area.  OsmAnd+ seems to realize that I have missed some points along the route and thinks I really need to go through those missed points.  So, it will recalculate the route and tell me to get off at the next exit and re-enter the expressway going south until I have passed the rest area and come to the next exit where I am to get off and re-enter the expressway going north again and continue through the missed points on the route.  If I ignore the instructions (which, of course, I do) it will recalculate the route again and pick the next exit for me so I can re-enter the south-bound expressway. Eventually, it will give up and just continue along the original route without trying to backtrack.

Has anyone else experienced this and is there a way to eliminate this behavior?

[Bart Eisenberg]

Are you following a GPX route?  Or just a route calculated by OsmAnd?

[David Remelts]

I am quite certain that it was a GPX route.  My normal method is to use OsmAnd on my tablet to create the route and when I am satisfied with it I will save it as GPX and transfer it to the Android head unit in my truck which is running the same version of OsmAnd.  Then I will load that GPX file and start the navigation.

But, I think you are on to something.  I did have occasion to generate a route directly on the Android head unit in the truck and ran into an unexpected detour on the route.  OsmAnd did inform me that I had been off the route for two tenths of a mile (or whatever) but it never tried to make me go back and hit the points I had missed.

So, obviously, the next questions is: why do they behave differently?

[Bart Eisenberg]

While you're navigating with a GPX, press the the gear icon (Options)  in the directions menu and look at the setting: "Pass along entire track".  It should be disabled.  

[Bart Eisenberg]

In any case, navigating with a GPX is usually different than navigating with a generated route because the former doesn't take the underlying map into account. 

[David Remelts]

Bart, thanks for the tip about the "Pass along entire track" setting - I will test that the next chance I get.  I confess that there is so much about this app that I don't know yet but the more I do find out about it the more impressed I am with it.  I am beginning to learn that when it doesn't do what I expect not to blame the app but my own ignorance ;-)

But your comment about the difference between GPX and generated routes makes me start to question my normal method of using the app.  I still want to use my tablet to design the route because it is so much more convenient and comfortable to be sitting in the fifth-wheel planning the next day's leg of the journey than it is to sit in the cab of the truck to do it.  So, maybe rather than saving the route as a GPX I should just save the markers that were used to generate the route on the tablet, transfer them to the truck and regenerate the route.

And, speaking of differences between GPX and generated routes: I have discovered that if I want to reverse the route the GPX route will recalculate the route based solely on the end points, ignoring any waypoints that were used to create the original GPX route.  Whereas a generated route will retain the intermediate points, although they will have to be manually reordered.

So, all in all, it seems that there are many compelling reasons to use generated routes whenever possible.

Thanks again.

[Bart Eisenberg]

Hi David:  I haven't tested this much, but here on the board, people have suggested transferring just the markers (as you contemplate doing) as a GPX file, then on the Options menu after you begin navigation, enabling "Calculate route between points". That should generate a route that either follows, or at least approximates, the one you had in mind.  I would think that this generated route would be reversible.  

From the discussions here, I think this method is still experimental.  If you try it, please post your results.  

[Ik Beweeg]

Yes, very frustrating. A very stupid behaviour since it seems osmand does not flag intermediate points to improve route calculation as 'passed'.

The only solution I know, once you realise why you have such strange instructions, is to find a parking place (which on highways can take some time) and fix the route by removing such points yourself. Result: loss of time and money.

Op vrijdag 27 september 2019 21:37:17 UTC+2 schreef David Remelts:

[David Remelts]

Bart, I finally had a chance to test this.  I loaded a GPX route and exited the expressway at a rest area.  I made sure that "Pass along entire track" was turned off and got back on the expressway.  It still wanted me to get off at the next exit and double back.

I used a generated route and got off at the same rest area and when I got back on the expressway it continued along the intended route without doubling back.

I was really hoping that the "Pass along entire track" setting would do the trick because GPX routes are really convenient to use.  Oh well...

[Bart Eisenberg]

Hmmm.  Do you have "Calculate between points" enabled?  If so, I wonder if one of the points is actually on the wrong side of the highway, so that OsmAnd is trying to double back in order to reach it.  If that were the case, I would think that the doubling-back would happen whether you exited the expressway or not.  

I admit--I'm reaching here in search of a solution. At some point, that resembles a guess.  

[David Remelts]

Unless it is on by default I am certain that I did not enable "Calculate between points", but I will double-check when I get a chance.  

[Bart Eisenberg]

Also, how are you creating the GPX on your tablet? With OsmAnd?  Another app?  A website? 

[David Remelts]

I am using the same version of OsmAnd+ on the tablet.  Also the same map files. I suppose, as a test, I could use the tablet for navigating the GPX route instead of transferring  it to the Android head unit in the truck. That's what I used to do before I installed the Android head unit but the mount I had in the truck for the tablet placed the tablet on top of the dash and I had problems with overheating the tablet if I was driving into the sun.  I'll let you know the results when I get a chance to test it.

[Bart Eisenberg]

This morning as a test, I created a route, saved it as a GPX, and navigated it, but purposely drove on nearby parallel roads.  Once I detoured, the route at first doubled back as you describe.  Further down, it tried to get back to the GPX, sometimes resulting in a needless u-turn. After I passed the point where the two roads converged, so I was back on the GPX track, navigation returned to normal.  

Then I tried it with again with "Calculate OsmAnd route for first and last route segment" disabled.  This time on the parallel road, the route "pointed" at the GPX without backtracking. That is, it indicated I was off-course but didn't actually navigate me back to the GPX.

Neither approach is ideal, of course, and my route in a rural area isn't the same as an expressway, so this may or may not apply. 

[David Remelts]

Hmmm... that's interesting.  I will have to experiment with that setting.  In the rest area scenario, I think that might work if it simply indicates that I am off-route and points back to the route (I think I can find my way back onto the expressway without guidance ;-)  As long as it doesn't do the  double back thing  after I converge back on the original GPX route, that's good.

However, I can envision a scenario where it could be a problem if it does not actually recalculate the route to get you back on course.  A couple weeks ago we were going thru an unfamiliar city and they  had the street all torn up.  I had to deviate from the route and the detour was not marked at all.  OsmAnd did an excellent job of rerouting me and getting me to my destination.

So, like you said, it may not be ideal either way.

[Grzegorz Adamiak]

Hmmm... that's interesting.  I will have to experiment with that setting.  In the rest area scenario, I think that might work if it simply indicates that I am off-route and points back to the route (I think I can find my way back onto the expressway without guidance ;-)  As long as it doesn't do the  double back thing  after I converge back on the original GPX route, that's good.

However, I can envision a scenario where it could be a problem if it does not actually recalculate the route to get you back on course.  A couple weeks ago we were going thru an unfamiliar city and they  had the street all torn up.  I had to deviate from the route and the detour was not marked at all.  OsmAnd did an excellent job of rerouting me and getting me to my destination.

I do find the recalculation useful for my purpose, however the logic behind it is a bit awkward. Apparently it tries to reach the nearest point on the track in straight line, not by the road. See attached screenshot for illustration. I actually came to the town via the track, then turned left to go to a gas station, so I passed that points already. Osmand wanted to drive me back on the track instead of continuing at a junction. I didn't use the "pass along entire track" option.

Recalculation works exactly how described earlier by Bart i.e. eventually it picks up to continue from where you get back on the track. You may have an edge case.