Mistake in navigation - preference of worse road
  • Hi,
    I would like to report issue that happens in Navigator (older version and also 5.0).
    For some weird reason the app prefers worse road (actually very bad road) over normal asphald road.

    The problem occurs when you try to plan route from Kraliky in CZ to Roztoki in PL.
    Sample route here (sorry not going to bother with screens from the device unless necessary).

    What happens in mapfactor is that it selects the road that goes around Smreczyna, like this:

    I was there on vacation actually almost 2 years ago when I noticed this problem and I do not know what is the problem. Back there I edited the "wrong" road with surface=gravel, because it is not even a asphalt road.

    So we have designated first class road that crosses Smreczyna or third-class road without asphalt that is slightly shorter (and perhaps there is no speed limit because is outside town) but MUCH worse. The road is actually ok only for 1 care (so is no 2-lane road, but only 1 lane) and the surface is very poor. Unless it is destination this should not be preferred road.
    You can see on google how this road looks.

    Eithere there is some problem with the data itself (does not seem likely) or for some reason the algoritm prefers the bad road over the good road n.33
    When you extract data from OSM, do you take into account the road surface? I can understand that this road is selected as it is shorter and faster (no 50 kmh speed limit like via Smreczyna).
    And if this is algorithm problem than this somewhat undermines my trust into mapfactor navigator :(

    Thank you for looking into it.
  • 10 Comments sorted by
  • this seems to be error in free maps, with TomTom maps route is as per your first screenshot

    Free maps are created by volunteers at www.openstreetmaps.org - anybody can join and help to make maps better using their local knowledge. May be you can also contribute?
  • I'm an OSM editor, so no worries here.
    I just do not see the error there. The road is marked as lower category (third vs first class road) and also with poor sufrace (gravel vs asphalt). Seems OK to me. And since I dont know what attributes are imported from OSM to navigator maps, it's not easy fix.
    Is road surface imported?
  • With the PC-version and OSM I get the route of the first link. So there is may be not a problem with OSM. 
  • it could be that your map files are not the latest?
  • Poland.mca from 15.04.2019 (386.504 kb)
    Czech-Republik.mca from 22.04.2019 (171.998 kb)
  • This specific problem is there since summer 2017 when I first noticed it (always using mobile app - windows phone or android). Back there I entered surface=gravel on the "wrong" road to make it less "attractive" so to speak. I keep checking this every few months and always the mobile app prefers the wrong road. So I do not think this is a matter of specific version of the OSM maps.

    There is many fields not filled in on this specific road and I could updated some. Obviously I need to stick to OSM conventions and not change something only because it does not work in specific navigation program (eh in Magic Earth it selects the right road). But I do not have a clue which fields are taken into account. Surface does not seem to work. Maybe width? (the road is only 1 lane so cars cannot pass easily).
  • I think that problem is speed attributes
    route via section of road 33 is slower
  • The road n.33 is going through a village so there is limit to 50 kmh.
    the "unnamed road" has no limit (so I guess the country-wide limit for 90 kmh) applies. But it is not possible to drive 90kmh there trust me. Probably one cannot even drive that 50kmh but some 30kmh or so. The road is in bad shape. That is indicated by the surface=gravel tag.
    Currently there is no "average speed" or "travel speed" tag available in OSM as far as I know. (eg HERE mapcreator has this.... max speed limit and travel speed).

    So to my understanding it is up to the navigation software to decide. I'm pretty sure there is much more field or forest roads that do not have speed limit eg 20kmh (so technically it is 90) but no one wants to drive there.
  • With a different android mobile app also with maps based on OSM I get the route shown in link one.
  • try to reduce preference to 30% for local roads in settings/vehicle profiles/road restrictions

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