[mkgmap-dev] Commit: r868: Implement routing for .osm input files.

Tue Feb 10 19:16:47 GMT 2009

Hi Paul,

Thanks a lot for the feedback. From what you report, it sounds like 
the new map worked quite well with no really bad problems.

> Given that I'm comparing gmapsupp.img files for combined England,
> Scotland and Wales previously created by using osm2mp and mkgmap with
> .mp files and now directly with mkgmap from .osm files then the initial
> observations are:-
> 
> Using the osm2mp method gives a final file of 119.8MB where the direct
> conversion gives a final file of 103.7MB

Hmm, did it only include 90% of the roads?

> Support for roundabouts seems less well implemented. On approaching a
> roundabout I would previously receive an instruction to "Take 3rd exit
> at roundabout". Approaching the same roundabout I was simply told to
> "Keep left to Bloggs Road" even though I needed the 3rd exit.

OK - the attached new lines file should fix that (this goes in
resources/styles/default).

> Slightly different routes are now chosen. These are not wrong - Just
> different to before. e.g. Leaving work I always ignore the Garmin route
> as it's not the best. When it recalculated it previously chose the route
> I actually take. Using the new file it picked a different route which I
> had to ignore a second time before it chose the route I actually take.

Was the new route completely silly or merely sub-optimal? If the later,
how could it have improved the route?

Tweaking of the road classes and speeds in the lines file should alter the
behaviour so you could try adjusting those values. I thought I had set
them to the same values used by osm2mp.

> I also noticed today that with both versions of the .img file any
> routing from the Rochdale area along the M62 fails at around the point
> that the M621 splits from the M62 (approximately J27). I realise there
> could be many reasons for this but I thought I'd mention it.

Does a split between map tiles occur there?

> For information purposes the pseudo code I use to create the files is:-
> 
> java -jar splitter.jar england.osm
> osm2mp.pl --nocodepage  --splitroads *.osm > e*.mp (5 files total)
> java -Xmx2048M -jar mkgmap.jar --latin1 --gmapsupp --route e?.mp
> wales.mp scotland.mp
> 
> java -jar splitter.jar england.osm
> java -Xmx2048M -jar mkgmap.jar --latin1 --gmapsupp --route e?.osm
> wales.osm scotland.osm

Cheers,

Mark
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