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[mkgmap-dev] My findings about the crash in MapSource

From Gerd Petermann gpetermann_muenchen at hotmail.com on Sat Feb 3 07:37:37 GMT 2018

Hi Andrzej,
I've uploaded my test data:
http://files.mkgmap.org.uk/download/411/baddem6.7z

Please adjust the hard coded paths so that splitter r590 and mkgmap r4102 are used.

The script produces a few small tiles with splitter and 4 maps with slightly different options

I think the hgt file in SRTM3_orig contains no voids, so I created a copy and placed a few voids (0x8000) into it.
Those voids appear only in tile 63240004.

The file crash.gdb contains two routes crossing tiles. The one starting in City park causes crashes
in MapSource (version 6.16.3) when you don't use the map in folder map\orig\OSM map.gmap
This changes when you compile r4102 with the no-dem-align.patch.

The other route never causes a crash because all tiles have no extra flag.
This changes when you use r4100.

My current understanding is that there is a problem when mkgmap r4102 writes tiles with the has extra flag set to true.
All routes crossing tile borders of those tiles seem to produce the crash.

BTW: BuildDEMFile doesn't align and produces DEM which doesn't crash.
That's why I thought that the alignment might be the problem.

I guess that we should increase or decrease the overlap of the DEM tiles.

Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Gerd Petermann <gpetermann_muenchen at hotmail.com>
Gesendet: Freitag, 2. Februar 2018 22:27
An: Development list for mkgmap
Betreff: Re: [mkgmap-dev] My findings about the crash in MapSource

Hi Andrzej,

I also think that it could be related to the alignment of DEM tiles.

I think the problem is not (only) related to dem-polygon, you should be able to reproduce
it when you change line 109 in DEMSection.java from
                boolean hasExtra = false;
to
                boolean hasExtra = true;


The polygon handling simply forces that this variable is set to true
and when this happens I see the crashes, although it only changes the size of the header info.

I'll prepare a test set tomorrow.

Gerd


________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Andrzej Popowski <popej at poczta.onet.pl>
Gesendet: Freitag, 2. Februar 2018 22:14
An: mkgmap-dev at lists.mkgmap.org.uk
Betreff: Re: [mkgmap-dev] My findings about the crash in MapSource

Hi Gerd,

maybe this is a problem of overlapping of DEM form different tiles? Or
maybe size of DEM area is calculated incorrectly?

Could you upload an example? I haven't used dem-poly on my maps and
never noticed this problem.

--
Best regards,
Andrzej
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