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[mkgmap-dev] splitter r325: improved split algo and new option

From Gerd Petermann gpetermann_muenchen at hotmail.com on Thu May 8 09:01:13 BST 2014

Hi Lambertus,

maybe also look at 
https://wiki.openstreetmap.org/wiki/Mkgmap/help/splitter#Tuning

(the page needs some updates, but that part is correct)

Gerd

> Date: Thu, 8 May 2014 09:31:28 +0200
> From: osm at na1400.info
> To: mkgmap-dev at lists.mkgmap.org.uk
> Subject: Re: [mkgmap-dev] splitter r325: improved split algo and new option
> 
> Thanks Gerd! This is valuable information for those of us processing 
> large areas of the planet.
> 
> Unfortunately there is no additional speedup for me because I already 
> use o5m because of osmupdate (to keep a local planet copy up-to-date).
> 
> On 07/05/2014 11:59, Gerd Petermann wrote:
> > Hi Felix,
> >
> > try o5m for both input and output, it is much faster.
> > The command
> > osmcovert --drop-version europe-latest.osm.pbf -o=europe.o5m
> > runs quite fast (~70 seconds on my machine),
> > the o5m file is ~2.430 MB, the pbf file has 2.104 MB.
> >
> > Splitter is much faster reading from o5m when
> > the keep-complete option is in use.
> > (210 secs for the o5m, 441 for pbf)
> >
> > With --output=pbf both are slower, and mkgmap is also much slower.
> >
> > All times with I/O on one normal hard disk. Even better results if you have
> > two different disks for reading and writing.
> >
> > Gerd
> >
> > ------------------------------------------------------------------------
> > Date: Wed, 7 May 2014 11:37:58 +0200
> > From: extremecarver at gmail.com
> > To: mkgmap-dev at lists.mkgmap.org.uk
> > Subject: Re: [mkgmap-dev] splitter r325: improved split algo and new option
> >
> > Well I still use pbf and not o5m.
> > First pbf is smaller..
> > Second - Geofabrik only offers pbf - that's why I stayed with it.
> >
> > I don't think I can cut a lot of time by first converting to 05m, then
> > hand it over to splitter...
> > Actually I also let splitter output pbf... Maybe I could change that in
> > future to 05m..
> > On 07.05.2014 11:36, Gerd Petermann wrote:
> >
> >     Hi Felix,
> >
> >     well, nowadays splitter performance mostly depends on I/O if you use
> >     o5m format
> >     for input and output and give enough heap.
> >
> >     Reg. mkgmap performance improvements: yes, that's what I expected.
> >     In short, the branch improved the evaluation of tags and the
> >     creation of the NOD file.
> >
> >     Gerd
> >
> >
> >     ------------------------------------------------------------------------
> >     Date: Wed, 7 May 2014 11:29:10 +0200
> >     From: extremecarver at gmail.com <mailto:extremecarver at gmail.com>
> >     To: mkgmap-dev at lists.mkgmap.org.uk
> >     <mailto:mkgmap-dev at lists.mkgmap.org.uk>
> >     Subject: Re: [mkgmap-dev] splitter r325: improved split algo and new
> >     option
> >
> >     Well - I'll update all my maps on Thursday again, to recheck. Maybe
> >     it has to do with increasing-maxnodes? Though I thought the higher
> >     the max-nodes, the faster...
> >     And I only meant splitter. I upgraded mkgmap at the same time (now
> >     integrating performance branch changes) - so mkgmap by itself got
> >     faster (though it depends on the country - seems like well mapped
> >     countries profit a lot more (e.g. Austria like 30% time off), than
> >     countries where few continue commands will be in action cause their
> >     mapping is basic like Asia).
> >
> >     I'm not using any pre-split files or cached files of any sort either...
> >     On 07.05.2014 06:49, Gerd Petermann wrote:
> >
> >         Hi Felix,
> >
> >         reg. speed: I can't reproduce that. I compared a split of Germany,
> >         both versions (r321 and r325) are more or less running the same
> >         time.
> >         (I've executed both programs two times to make sure that disk
> >         caches
> >         are not causing big differences)
> >
> >         Or did you mean the combination of splitter + mkgmap to process
> >         e.g. Asia?
> >
> >         Gerd
> >
> >         ------------------------------------------------------------------------
> >         Date: Tue, 6 May 2014 18:22:00 +0200
> >         From: extremecarver at gmail.com <mailto:extremecarver at gmail.com>
> >         To: mkgmap-dev at lists.mkgmap.org.uk
> >         <mailto:mkgmap-dev at lists.mkgmap.org.uk>
> >         Subject: Re: [mkgmap-dev] splitter r325: improved split algo and
> >         new option
> >
> >         Seems to be much better now. I don't think I can increase the
> >         max-nodes value though, but for most maps the new algo creates
> >         less tiles for the same max-nodes value (e.g. Austria from 43
> >         down to 35 for me, with the smallest tile now around 5MB instead
> >         of 2.8, and the biggest 12MB instead of 11MB, for Asia I
> >         simultaneously increased max-nodes from 800k to 900k- so I'm
> >         down from 624 tiles to 493.... and size from 970KB-16MB to now
> >         ). So it still seems to depend on the country, but it's already
> >         a lot better...
> >         It's a bit slower (about 10% more time)
> >
> >         On 06.05.2014 13:56, Gerd Petermann wrote:
> >
> >             Hi all,
> >
> >             I've applied num-tiles-v1.patch  and improved the split
> >             algo, see
> >             http://gis.19327.n5.nabble.com/mkgmap-ToDo-list-tp5803388p5805165.html
> >
> >
> >             It is now less likely that splitter creates tiles with a low
> >             number of
> >             nodes, it is more likely that all tiles have nearly the same
> >             number of nodes,
> >             and typically you will see fewer tiles.
> >             Maybe this also means that you can increase the max-nodes value.
> >
> >             I hope this also reduces the need for complex interactions
> >             between
> >             spltter and mkgmap.
> >
> >
> >
> >             Gerd
> >
> >
> >             _______________________________________________
> >             mkgmap-dev mailing list
> >             mkgmap-dev at lists.mkgmap.org.uk  <mailto:mkgmap-dev at lists.mkgmap.org.uk>
> >             http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> >
> >
> >         --
> >         keep on biking and discovering new trails
> >
> >         Felix
> >         openmtbmap.org &www.velomap.org  <http://www.velomap.org>
> >
> >
> >         _______________________________________________ mkgmap-dev
> >         mailing list mkgmap-dev at lists.mkgmap.org.uk
> >         <mailto:mkgmap-dev at lists.mkgmap.org.uk>
> >         http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> >
> >
> >         _______________________________________________
> >         mkgmap-dev mailing list
> >         mkgmap-dev at lists.mkgmap.org.uk  <mailto:mkgmap-dev at lists.mkgmap.org.uk>
> >         http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> >
> >
> >     --
> >     keep on biking and discovering new trails
> >
> >     Felix
> >     openmtbmap.org &www.velomap.org  <http://www.velomap.org>
> >
> >
> >     _______________________________________________ mkgmap-dev mailing
> >     list mkgmap-dev at lists.mkgmap.org.uk
> >     <mailto:mkgmap-dev at lists.mkgmap.org.uk>
> >     http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> >
> >
> >     _______________________________________________
> >     mkgmap-dev mailing list
> >     mkgmap-dev at lists.mkgmap.org.uk  <mailto:mkgmap-dev at lists.mkgmap.org.uk>
> >     http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> >
> >
> > --
> > keep on biking and discovering new trails
> >
> > Felix
> > openmtbmap.org &www.velomap.org  <http://www.velomap.org>
> >
> >
> > _______________________________________________ mkgmap-dev mailing list
> > mkgmap-dev at lists.mkgmap.org.uk
> > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> >
> >
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> > mkgmap-dev at lists.mkgmap.org.uk
> > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> >
> 
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