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[solved]Routing problem Dresden - Prague
http://forum.navit-project.org/viewtopic.php?f=8&t=443
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Author:  tauso [ 29 Sep 2013, 10:34 ]
Post subject:  [solved]Routing problem Dresden - Prague

I'm using the newest svn version of navit with a map extracted from maps.navit-project.org and have a problem with routing between
Dresden (Germany) and Prague (Czech Republic).

I'ts not possible to route directly between the following points:

50°2'20" N 13°43'11" E
Leubnitzer Straße, Dresden, Germany

50°7'30 N 14°30'52" E
Listova, Praha (Letnany), Czech Republic

If I set a destination between these two points (somewhere on highway D8 above Prague), then the routing works.

I've also played around with the "route_depth" paramater, but the problem persists. And I don't think of a memory problem, because I tested it on my deskop PC with 4GB RAM (Ubuntu 13.04 64bit) with the demo vehicle.

Maybe it's a connection error somewhere on the map itself, but why is routing working with the second destination?

Author:  usul [ 29 Sep 2013, 10:41 ]
Post subject:  Re: Routing propblem Dresden - Prague

Hmm, sad to hear :(
Can you please give us some more details?
  • date of the map and if single mappackage or multiple ones?
  • vehicle used for routing?results for changed vehicle?

IMHO the working with a via-point might indicate that there is a problem with the deeph indeed, as AFAIK the routing iterates from waypoint to waipoint and thus would have a different deeph/filte if you add a new via point :/

Author:  tauso [ 29 Sep 2013, 11:03 ]
Post subject:  Re: Routing propblem Dresden - Prague

usul wrote:
  • date of the map and if single mappackage or multiple ones?


I've downloaded the map today, but map version was 130926 and it's the only binfile in the maps folder.

Quote:
  • vehicle used for routing?results for changed vehicle?


Ok, thanks for the tip. I've used the demo vehicle "Car" and changed it:

Code:
<vehicle name="Demo" profilename="car_shortest" active="1" source="demo://" />
navit:route_path_new:no route found, pos blocked
<vehicle name="Demo" profilename="car_avoid_tolls" active="1" source="demo://" />
navit:route_path_new:no route found, pos blocked
<vehicle name="Demo" profilename="car_pedantic" active="1" source="demo://" />
navit:command_new:entry 276 exit 20


So "car pedantic" is working. I'll take a look in the "route_depth" values.

Author:  xenos1984 [ 29 Sep 2013, 12:13 ]
Post subject:  Re: Routing propblem Dresden - Prague

It should be this problem:

http://trac.navit-project.org/ticket/456

Yes, changing the routing behaviour is the way to go. Maybe we can make car-pedantic the default...

Author:  usul [ 29 Sep 2013, 12:22 ]
Post subject:  Re: Routing propblem Dresden - Prague

I think that user:Xenos1984 had an issue where the search around a startpoint didn't found a residential road, because the "car" profile has a very limited value. The pendantic seems to be a bit more robust.

IMHO this would be worth for a TRAC ticket?

Author:  Mapmapper [ 29 Sep 2013, 18:58 ]
Post subject:  Re: Routing problem Dresden - Prague

If the route starts in a street, that is not in the vehicle-Profile, then Navit is unable to find a route, because the start-point is unreachable. The same, if the street is marked as access=private. You need all type of streets in the profile. And start outside access=private/no etc.

In Standard-horse-Profile you often cannot start in a forest, because the horse-Profile has no track_grass und track_unpaved.

An other problem is to find a route near a coastline, wich has many curves, and the route has to go away from aim at first. There, a special route_depth is needed.

Author:  tauso [ 30 Sep 2013, 09:19 ]
Post subject:  Re: Routing problem Dresden - Prague

Mapmapper wrote:
If the route starts in a street, that is not in the vehicle-Profile, then Navit is unable to find a route, because the start-point is unreachable. The same, if the street is marked as access=private. You need all type of streets in the profile. And start outside access=private/no etc.


Interesting fact, but that's not the problem I have. Because routing from the same start point to a different destination works with the "car" profile. I'll use "car pedantic" for now or change the "route_depth" from "car".

Does the car pedantic setting of "18:40000" have some disadvantages (memory consumption? route accuracy?).

Author:  xenos1984 [ 30 Sep 2013, 10:44 ]
Post subject:  Re: Routing problem Dresden - Prague

tauso wrote:
Does the car pedantic setting of "18:40000" have some disadvantages (memory consumption? route accuracy?).


It should increase memory consumption and calculation time, since a larger portion of the map will be loaded at higher detail level (smaller roads), and more roads will be considered. This could be a problem on smaller embedded devices with limited memory and computing power, but otherwise should not be a problem.

Author:  Goverp [ 01 Oct 2013, 10:57 ]
Post subject:  Re: Routing problem Dresden - Prague

tauso wrote:
...
I'ts not possible to route directly between the following points:

50°2'20" N 13°43'11" E
Leubnitzer Straße, Dresden, Germany

50°7'30 N 14°30'52" E
Listova, Praha (Letnany), Czech Republic

If I set a destination between these two points (somewhere on highway D8 above Prague), then the routing works.
...
why is routing working with the second destination?

It's almost certainly the route depth processing. With the standard configuration, navit loads detailed map data for a square around each waypoint (including start and end), and less detailed data for a large square containing all the waypoints. It looks like somewhere near your D8 point, routes from Dresden to Listova require road segments that are in the detailed data but not the less detailed data. This probably means the OSM map rates the D8 (or some other required segment) as too low a quality to make it into the less detailed data.

This is both a strength and a weakness of navit. The use of less detailed data for the majority of the route both speeds navits route solving and eliminates the tendency of some navigation tools to send you on cart-track shortcuts in the middle of long journeys. The drawback is when the only route uses the cart-track, navit leaves you stranded.

I started work on an alternative route solving algorithm that should eliminate these problems, but I got interrupted by having to get my car ready to go on holiday, at which point I reverted to paper maps and a human navigator. They have strengths and weaknesses too - they always find a route, but have a GUI that argues with the driver. :roll:

Author:  tauso [ 30 Oct 2014, 12:48 ]
Post subject:  Re: Routing problem Dresden - Prague

I ran in the same problem again. But now, even car pedantic isn't working anymore.
Just tried it with the curent svn version (5914) and the demo vehicle on windows and the result is:

vehicleprofile: car: no route found
vehicleprofile: car-pedantic: crashes with:
Quote:
***MEMORY-ERROR***: : GSlice: failed to allocate 4096 bytes (alignment: 4096): unknown error

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

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