Strange long distance routes on Nüvi

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Strange long distance routes on Nüvi

Bodo Pfelzer
I use a gmapsupp.img generated with a reduced  style derived from the default mkgmap-style . Routing for cars works fine, if the routes are short. But if I try to plan a long journey (1000 km). The route calculation gets stuck for some minutes at lets say 80 percent and finally comes to a result. But the resulting route is something that looks like a concatenation of beelines. My assumption is, that Nüvi contains an overview map of the world (or Europe) that I cannot disable. Could I replace it using --tdbfile in mkgmap? But the option mentions MapSource, I tried to avoid MapSource for now.

Routing works fine, if I disable Motorways (or toll roads), but the route seems to be somewhat inconvenient.

Perhaps my questions is a little bit outdated, since there are good smartphone based apps for navigation. But I love my old fashioned Nüvi. This leads to the next question: Is there a chance that there will be TMC information compiled into mkgmap maps sometimes in the future? As far as I understand, nobody knows where it is stored inside encrypted proprietary maps.

Best regards
Bodo

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Re: Strange long distance routes on Nüvi

Nevw
TMC abbreviation:
Traffic Message Channel (TMC) is a technology for delivering traffic and travel information to motor vehicle drivers. .... have to be superimposed onto maps bymapping the reported location ...

N

On 27 Jul 2017, at 1:46 am, Bodo Pfelzer <[hidden email]> wrote:

I use a gmapsupp.img generated with a reduced  style derived from the default mkgmap-style . Routing for cars works fine, if the routes are short. But if I try to plan a long journey (1000 km). The route calculation gets stuck for some minutes at lets say 80 percent and finally comes to a result. But the resulting route is something that looks like a concatenation of beelines. My assumption is, that Nüvi contains an overview map of the world (or Europe) that I cannot disable. Could I replace it using --tdbfile in mkgmap? But the option mentions MapSource, I tried to avoid MapSource for now.

Routing works fine, if I disable Motorways (or toll roads), but the route seems to be somewhat inconvenient.

Perhaps my questions is a little bit outdated, since there are good smartphone based apps for navigation. But I love my old fashioned Nüvi. This leads to the next question: Is there a chance that there will be TMC information compiled into mkgmap maps sometimes in the future? As far as I understand, nobody knows where it is stored inside encrypted proprietary maps.

Best regards
Bodo
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Re: Strange long distance routes on Nüvi

Colin Smale

What needs to be embedded into the map, is the Location Table which maps the location IDs in the TMC messages to roads, junctions etc in the map network. The radio messages only contain location IDs, not lat/lon.

Not all location tables are available as open data - each country has its own ideas. I believe that the German OSM community has done quite a bit of work on TMC in OSM, probably including the Location Table data. But who knows how that information needs to be encoded in a Garmin map...

//colin

 


On 2017-07-26 22:47, nwastra wrote:

TMC abbreviation:
Traffic Message Channel (TMC) is a technology for delivering traffic and travel information to motor vehicle drivers. .... have to be superimposed onto maps bymapping the reported location ...

N

On 27 Jul 2017, at 1:46 am, Bodo Pfelzer <[hidden email]> wrote:

I use a gmapsupp.img generated with a reduced  style derived from the default mkgmap-style . Routing for cars works fine, if the routes are short. But if I try to plan a long journey (1000 km). The route calculation gets stuck for some minutes at lets say 80 percent and finally comes to a result. But the resulting route is something that looks like a concatenation of beelines. My assumption is, that Nüvi contains an overview map of the world (or Europe) that I cannot disable. Could I replace it using --tdbfile in mkgmap? But the option mentions MapSource, I tried to avoid MapSource for now.

Routing works fine, if I disable Motorways (or toll roads), but the route seems to be somewhat inconvenient.

Perhaps my questions is a little bit outdated, since there are good smartphone based apps for navigation. But I love my old fashioned Nüvi. This leads to the next question: Is there a chance that there will be TMC information compiled into mkgmap maps sometimes in the future? As far as I understand, nobody knows where it is stored inside encrypted proprietary maps.

Best regards
Bodo
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Re: Strange long distance routes on Nüvi

Gerd Petermann
In reply to this post by Bodo Pfelzer
Hi Bodo,

the --tdbfile option has no effect on the created gmapsupp. My understanding reg. long distance routing on the device is that the algorthm needs memory which is limited.
On my Oregon this typically results in one straigt line after minutes. Maybe the nüvi uses a different algo. It would be interesting to know if you can reproduce the problems
in Mapsource because that would allow us to reproduce them as well.
I stopped using the device for long distance routing (> 50 km), I use internet services now and download the routes as tracks.
I can only suggest to avoid long distance routing by adding additional points.

ciao,
Gerd
________________________________________
Von: mkgmap-dev <[hidden email]> im Auftrag von Bodo Pfelzer <[hidden email]>
Gesendet: Mittwoch, 26. Juli 2017 17:46:20
An: [hidden email]
Betreff: [mkgmap-dev] Strange long distance routes on Nüvi

I use a gmapsupp.img generated with a reduced  style derived from the default mkgmap-style . Routing for cars works fine, if the routes are short. But if I try to plan a long journey (1000 km). The route calculation gets stuck for some minutes at lets say 80 percent and finally comes to a result. But the resulting route is something that looks like a concatenation of beelines. My assumption is, that Nüvi contains an overview map of the world (or Europe) that I cannot disable. Could I replace it using --tdbfile in mkgmap? But the option mentions MapSource, I tried to avoid MapSource for now.

Routing works fine, if I disable Motorways (or toll roads), but the route seems to be somewhat inconvenient.

Perhaps my questions is a little bit outdated, since there are good smartphone based apps for navigation. But I love my old fashioned Nüvi. This leads to the next question: Is there a chance that there will be TMC information compiled into mkgmap maps sometimes in the future? As far as I understand, nobody knows where it is stored inside encrypted proprietary maps.

Best regards
Bodo
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Re: Strange long distance routes on Nüvi

Michael Poesdorf
Hi,

I'm using my maps even for long distance routing. Typically 600-800  
km, Germany to Italy or Spain, Germany to UK.
My device is a Montana 600/610. I do not use my maps on the pc  
(mapsource, etc).
Adding additional (way)points helps me to control the exact route.

Regards, Michael


Zitat von Gerd Petermann <[hidden email]>:

> Hi Bodo,
>
> the --tdbfile option has no effect on the created gmapsupp. My  
> understanding reg. long distance routing on the device is that the  
> algorthm needs memory which is limited.
> On my Oregon this typically results in one straigt line after  
> minutes. Maybe the nüvi uses a different algo. It would be  
> interesting to know if you can reproduce the problems
> in Mapsource because that would allow us to reproduce them as well.
> I stopped using the device for long distance routing (> 50 km), I  
> use internet services now and download the routes as tracks.
> I can only suggest to avoid long distance routing by adding  
> additional points.
>
> ciao,
> Gerd
> ________________________________________
> Von: mkgmap-dev <[hidden email]> im Auftrag  
> von Bodo Pfelzer <[hidden email]>
> Gesendet: Mittwoch, 26. Juli 2017 17:46:20
> An: [hidden email]
> Betreff: [mkgmap-dev] Strange long distance routes on Nüvi
>
> I use a gmapsupp.img generated with a reduced  style derived from  
> the default mkgmap-style . Routing for cars works fine, if the  
> routes are short. But if I try to plan a long journey (1000 km). The  
> route calculation gets stuck for some minutes at lets say 80 percent  
> and finally comes to a result. But the resulting route is something  
> that looks like a concatenation of beelines. My assumption is, that  
> Nüvi contains an overview map of the world (or Europe) that I cannot  
> disable. Could I replace it using --tdbfile in mkgmap? But the  
> option mentions MapSource, I tried to avoid MapSource for now.
>
> Routing works fine, if I disable Motorways (or toll roads), but the  
> route seems to be somewhat inconvenient.
>
> Perhaps my questions is a little bit outdated, since there are good  
> smartphone based apps for navigation. But I love my old fashioned  
> Nüvi. This leads to the next question: Is there a chance that there  
> will be TMC information compiled into mkgmap maps sometimes in the  
> future? As far as I understand, nobody knows where it is stored  
> inside encrypted proprietary maps.
>
> Best regards
> Bodo
> _______________________________________________
> mkgmap-dev mailing list
> [hidden email]
> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev



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Re: Strange long distance routes on Nüvi

popej
In reply to this post by Bodo Pfelzer
Hi,

I think TMC is supported only by NT maps. There should be TMC ID
somewhere in img and there is additional file with extension *.trf in
mapset, similarly like global index. It would need a lot of revers
engineering to find how it all works. And there is not much TMC data in
OSM. Probably only in Germany.

I have done some work in my own styles to improve long distance routing.
This include recognizing international roads and increase of road class
for junctions. I will try to prepare a patch for default style.

--
Best regards,
Andrzej
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Re: Strange long distance routes on Nüvi

popej
Hi,

here is attached my proposition for improving long distance routing.
Please test and check if it helps.

--
Best regards,
Andrzej

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Re: Strange long distance routes on Nüvi

Bodo Pfelzer-2
In reply to this post by popej

Hi Andrzej,

thanks. The patch helped a lot. Now my device is able to calculate the routes. Unfortunately I don't understand the essential trick. As a side effect, the patch seems to annul my toll avoidance coded in "inc/roadspeed".  There I reduced mkgmap:road-speed-max by one for all toll roads, that must be paid per kilometre. Do you think it is possible to keep the modified road_speeds?


Am 27.07.2017 um 13:08 schrieb Andrzej Popowski:
Hi,

I think TMC is supported only by NT maps. There should be TMC ID somewhere in img and there is additional file with extension *.trf in mapset, similarly like global index. It would need a lot of revers engineering to find how it all works. And there is not much TMC data in OSM. Probably only in Germany.

I have done some work in my own styles to improve long distance routing. This include recognizing international roads and increase of road class for junctions. I will try to prepare a patch for default style.


-- 
Bodo Pfelzer                          Fon: +49 2103 33993-14
                                      Fax: +49 2103 33993-10

Business-Logics GmbH                  Amtsgericht Düsseldorf
Telleringstraße 11                    HRB 50613
40721 Hilden                          Geschäftsführer: 
                                      Dr. Bodo Pfelzer, Ralf Reddin, Holger Wiechert

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Re: Strange long distance routes on Nüvi

Bodo Pfelzer

OK, this seems to be a device artefact. If I split the route in two halves again, the non-toll short cut is chosen again.



Am 28.07.2017 um 21:32 schrieb Bodo Pfelzer:

Hi Andrzej,

thanks. The patch helped a lot. Now my device is able to calculate the routes. Unfortunately I don't understand the essential trick. As a side effect, the patch seems to annul my toll avoidance coded in "inc/roadspeed".  There I reduced mkgmap:road-speed-max by one for all toll roads, that must be paid per kilometre. Do you think it is possible to keep the modified road_speeds?


Am 27.07.2017 um 13:08 schrieb Andrzej Popowski:
Hi,

I think TMC is supported only by NT maps. There should be TMC ID somewhere in img and there is additional file with extension *.trf in mapset, similarly like global index. It would need a lot of revers engineering to find how it all works. And there is not much TMC data in OSM. Probably only in Germany.

I have done some work in my own styles to improve long distance routing. This include recognizing international roads and increase of road class for junctions. I will try to prepare a patch for default style.


-- 
Bodo Pfelzer                          Fon: +49 2103 33993-14
                                      Fax: +49 2103 33993-10

Business-Logics GmbH                  Amtsgericht Düsseldorf
Telleringstraße 11                    HRB 50613
40721 Hilden                          Geschäftsführer: 
                                      Dr. Bodo Pfelzer, Ralf Reddin, Holger Wiechert

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Re: Strange long distance routes on Nüvi

popej
Hi Bodo,

I think Garmin is using some kind of hierarchical routing algorithm. It
looks like GPS uses only class 4 and 3 roads for long distances (at
least in case of recent nuvis, hiking GPS can be more flexible). For
proper routing GPS needs a continuous and reasonably dense notwork of
high class roads.

My patch address 2 problems in default style.

First are links and roundabouts, which often get lower road class than
connected roads. This breaks continuity of high class network and breaks
routing. My patch simply increases road class for many links and
roundabout types.

Second problem is low density of good highways in some regions. To make
it better, my patch increases road class for international roads. These
roads are detected by "ref" and "int_ref" tags, both in objects and
relations.

I have added some small general corrections for
"highway=mini_roundabout", "access=hov" and "oneway=reversible".

There is no direct change for "inc\roadspeed". Maybe patch overrides
some of your changes in "lines" file? Anyway, I don't think road speed
breaks routing, you can tune it to your liking.

--
Best regards,
Andrzej
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Re: Strange long distance routes on Nüvi

Gerd Petermann
Hi Andrzej,

I looked at your patch and it seems reasonable to me but
as a cyclist I'd prefer to use a different tag instead of mkgmap:good_road,
maybe mkgmap:fast_road?
Do you know how this patch influences bicycle routing?

The special handling of highway=mini_roundabout is somewhat problematic
because that tag should not be used on ways. I also would not use the type 0x0c
for them, so I suggest to remove that rule so that our "mop up" rule catches them:

# Mop up any unrecognised highway types
highway=* & area!=yes [0x07 road_class=0 road_speed=0 resolution 23]
 
Gerd

popej wrote
Hi Bodo,

I think Garmin is using some kind of hierarchical routing algorithm. It
looks like GPS uses only class 4 and 3 roads for long distances (at
least in case of recent nuvis, hiking GPS can be more flexible). For
proper routing GPS needs a continuous and reasonably dense notwork of
high class roads.

My patch address 2 problems in default style.

First are links and roundabouts, which often get lower road class than
connected roads. This breaks continuity of high class network and breaks
routing. My patch simply increases road class for many links and
roundabout types.

Second problem is low density of good highways in some regions. To make
it better, my patch increases road class for international roads. These
roads are detected by "ref" and "int_ref" tags, both in objects and
relations.

I have added some small general corrections for
"highway=mini_roundabout", "access=hov" and "oneway=reversible".

There is no direct change for "inc\roadspeed". Maybe patch overrides
some of your changes in "lines" file? Anyway, I don't think road speed
breaks routing, you can tune it to your liking.

--
Best regards,
Andrzej
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Re: Strange long distance routes on Nüvi

popej
Hi Gerd,

mkgmap:fast_road is OK. I was looking for shorter synonym of
important_road, "fast" fits well enough.

I have no experience with bicycle routing. Maybe someone else could comment.

I prefer to put min_roundabout explicitly, since I don't use mop up rule
for my car maps. I guess type 0x07 could be used too, don't know which
is more appropriate for this object.

--
Best regards,
Andrzej
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