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[mkgmap-dev] Memory limits for mkgmap and splitter

From Chris Miller chris.miller at kbcfp.com on Wed Aug 5 18:25:15 BST 2009

I've built a new version that *might* be able to handle the planet OK. I 
don't know how many areas North America breaks in to, but if you're able 
to handle 255 areas (at 1,600,000 nodes each) with an older version of the 
splitter, then I think this version should work for the whole planet:


If you still can't get it to work but are able to at least generate areas.list, 
then you could try reducing the number of nodes per area since that will 
directly reduce the amount of memory required when the split files are being 
written out.

Assuming no one finds any serious problems with this build, I'll get it checked 
in and released properly so everyone can benefit.


> My latest changes were just quick fixes to get relations and 256+
> tiles working, there's still more that needs to be done before this is
> really useful. In particular, I need to prevent the splitter from
> hanging on to node and way information that it doesn't need for a
> given set of 255 areas. In other words, currently the memory
> requirements will still be very large and you don't stand much chance
> of splitting the planet file. I'll do some further work to try and
> reduce this, I think there's a couple of easy wins.
> You might be able to split America though, if you do attempt it please
> let me know how it goes.
>> Thanks for your work on this, much appreciated!
>> I'm trying to get a grip on how to use this version of splitter and
>> re-read your mail a few times. I hope I understand it:
>> So this version should eliminate the need to split the planet with
>> Osmosis before giving it to splitter. Just provide the planet and
>> splitter will define around 500 tiles and reprocess the planet a few
>> times to get all the tiles extracted.
>> I'll start a test run with the latest planet tonight. If it doesn't
>> work on my 4GB machine then I'll try the America's extract made with
>> Osmosis and report back.

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