[mkgmap-dev] Memory limits for mkgmap and splitter

Wed Aug 5 15:31:56 BST 2009

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.

Chris Miller wrote:
> I've now made some changes that remove the 4-area per relation limit and 
> also the 255 tile limit. The 255 tile fix is just a workaround for now, it 
> requires a full reprocess for each set of 255 tiles rather than tackling 
> them all in a single pass. This will still be significantly better than only 
> processing 4 areas at a time however.
> 
> I've made some code changes to allow more than 4 areas per relation and more 
> than 255 tiles per split. I won't have time to commit these changes until 
> I get home later this evening. If you want to try it out in the meantime 
> you can download a version from here (please treat this as a very unofficial 
> and beta-quality release!):
> 
> http://redyeti.net/splitter.jar
> 
> Here's what's changed from the version that's currently in the codestore:
> 
> - Replaced the SAX parser with XPP for modest performance and memory benefits
> - Improved program output to give more detail about what's going on (work 
> in progress)
> - Removed limit of 4 areas per relation (no memory or performance penalty)
> - Removed limit of 255 areas per split. When there are more than 255 areas, 
> multiple passes are made with up to 255 areas processed per pass
> 
> Any feedback, questions or suggestions are welcome. I haven't tried this 
> on anything as big as North/South America yet, would be very interested to 
> hear how it goes.
> 