[mkgmap-dev] splitter: option for maximum tile area?

Thu Nov 1 08:32:03 GMT 2018

Hi Bernhard,

I tried to reproduce the memory problems with tile 47120005. I don't think that the sea itself is a problem here, at least not when you use the --precomp-sea option. It took only 15 secs to process that tile with asia data from August with the default style and typical options for routing etc.
My input file didn't contain SRTM data so I assume this is the reason. Maybe you have many contour lines with ele=0 in your data?

Gerd

________________________________________
Von: Gerd Petermann <gpetermann_muenchen at hotmail.com>
Gesendet: Mittwoch, 31. Oktober 2018 22:49
An: Gerd Petermann; Development list for mkgmap
Betreff: AW: [mkgmap-dev] splitter: option for maximum tile area?

Hi Bernhard,

looked again at the splitter command in your last post. You also use a rather high max-nodes value.
Such a high value means that you get rather large tiles and that mkgmap needs more memory for each tile
compared to the default 1400000. Many users use a value near 1200000.

Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Gerd Petermann <gpetermann_muenchen at hotmail.com>
Gesendet: Mittwoch, 31. Oktober 2018 22:20
An: Development list for mkgmap
Betreff: Re: [mkgmap-dev] splitter: option for maximum tile area?

Hi Bernhard,
there is no option for this. Do you use option --precomp-sea in splitter? Maybe you use --no-trim ?
If that doesn't help you can try to change the values for
private static final int MAX_LAT_DEGREES = 85;
private static final int MAX_LON_DEGREES = 90;
in SplittableDensityArea.java and compile your own version of splitter.

Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Bernhard Hiller <bhil at gmx.de>
Gesendet: Mittwoch, 31. Oktober 2018 22:03
An: mkgmap-dev at lists.mkgmap.org.uk
Betreff: [mkgmap-dev] splitter: option for maximum tile area?

Hi all,
currently a Java OutOfMemory exception prevents me from creating a map.
I already use option --max-jobs=3 (the machine has 4 physical cores) and
-Xmx5G (of 8 GB installed). Beyond OSM data, the map contains DEM and
elevation contour lines.
 From the tiles finished and those with a new timestamp but about 0
bytes length, I can see that mkgmap was rendering tiles 47120005,
47120006, 47120007 at the time of crash.
Tile 47120005 is extremely large by physical area - some 6° x 5.5° (see
attached file), covering a lot of the south chinese sea, i.e. there are
not many actual data in that area.
I guess that the problem arises with that tile. I remember some case in
the past where a single tile covering such a large area of mainly sea
caused mkgmap to take an enormous amount of time for rendering - also
here, mkgmap already spent about 1 hour before crashing.
So I'd like to ask: is there some possibility for limiting the area of a
tile among the splitter options?
Kind regards,
Bernhard
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