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[mkgmap-dev] Splitter --cache parameter

From Chris Miller chris.miller at kbcfp.com on Tue Sep 1 12:56:23 BST 2009

L> I don't know what change made it possible, but I finally succeeded to
L> process all of North/South America with the latest splitter and 3.9
L> GB heap space. I used the cache option and max-node=1.2 million. I've
L> tried this a few times before with older splitter versions, but this
L> is the first time the split finished without fatal errors. So I
L> finally have correct tiles for North America (at least the ones that
L> got rendered by Mkgmap successfully!):
L> http://garmin.na1400.info/routable.php

That's great news. I've made various small changes to the splitter over the 
past couple of weeks in an attempt to squeeze as much performance while using 
as little memory as possible, but nothing too significant so perhaps it's 
just a combination of everything that has just got you under the threshold.

L> I guess it's time for me to start hacking on a areas.kml editing tool
L> to get rid of all those red tiles :-) Or is the node density code
L> already functional?

Have you tried the .kml import? I checked this in a few days ago - you can 
just pass in a .kml file instead of areas.list, and everything should behave 
as it would with the areas.list file.

The node density stuff isn't done yet, but yesterday I found time to do some 
fairly big internal refactorings of the splitter in preparation for this. 
It hopefully won't take me too much longer to get the density map working, 
albeit with nodes only initially. This 'nodes only' approach will still split 
in exactly the same way as the current splitter, the big advantage it that 
it will require much much less memory to do so without any performance cost. 
Once I have the nodes only approach working I'll start to look at calculating 
densities for the ways and relations too. At this stage I can't see how to 
avoid having to make some big performance/memory tradeoffs to get that working 
though, so I'll probably keep it optional.


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