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[mkgmap-dev] Possible Indexing Problem

From Gerd Petermann gpetermann_muenchen at hotmail.com on Sun Mar 10 13:12:17 GMT 2019

OK, you can either download the source and compile on your own or use this binary:

The tool needs the current version of mkgmap.
I use it like this to analyse a gmapsupp in the current directory:
java -ea -Xmx6800m -cp d:\display\dist\display.jar;d:\mkgmap\dist\mkgmap.jar test.display.MdrDisplay gmapsupp.img  > mdr.out 2> mdr.err
Adapt the path to the jar files, on linux replace the semicolons ";" by colons ":"
I suggest to start with a small gmapsupp (e.g. with two or three *.img)
The output in stdout (mdr.out) is a rather large file showing the content of the index, it should start similar to this:
--------- Common Header --------------------------------------------------------
00000000 | 38 02                   | Header length 568
00000002 | 47 41 52 4d 49 4e 20 4d | File type GARMIN MDR
0000000a | 44 52                   |
0000000c | 01                      | ???
0000000d | 00                      | Set if locked

The program allows to reduce the output to the header and a single index section with option --print=<section-number>, e.g. --print=5 will only print section 5 (the cities)

Once you understand how to use the program you can try to compare the gmapsupp produced by mkgmap with that from Mapsource
to find differences. You'll need a good text file comparer to do this, it should display the two files side by side and highlight the differences, else you'll probably
lost ;) On Windows the compare tool in TotalCommander is a good choice.

See also https://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin/MDR_Subfile_Format

I hope you find something, my Garmin Oregon always ignores the index for restaurants (also with gmapsupp from Mapsource) but uses it for e.g. shops or hotels. I did not find a reason for that.


Von: Manfred Haiduk <manfred.haiduk at freenet.de>
Gesendet: Sonntag, 10. März 2019 13:35
An: Gerd Petermann; Development list for mkgmap
Betreff: Re: [mkgmap-dev] Possible Indexing Problem

I would appreciate to get more details :-) Where can i get this tool ?
BTW, it was the first time, since i'm using mkgmap to buld my maps for
the device, that the device will stuck while searching. So i assume,
something was wrong within the index.

Am 10.03.2019 um 13:19 schrieb Gerd Petermann:
> Hi Manfred,
> we have the display tool to analyse the index, but it will fail on a huge index as it has a hard coded limit of 50 tiles.
> However you should be able to display (convert to text) the basic structure with the tool and maybe that will help to find out what's wrong.
> If you are interested I can post more details.
> Gerd
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Manfred Haiduk <manfred.haiduk at freenet.de>
> Gesendet: Sonntag, 10. März 2019 12:57
> An: Development list for mkgmap
> Betreff: [mkgmap-dev] Possible Indexing Problem
> Hi all
> last week i was playing around building new maps with mkgmap 4282 and
> the default style. Building smaller maps, i.e Nordrhein Westfalen, i
> don't see any problems but the last map i tried out was complete
> germany. And now it seems, that my device (GPSMAP 276Cx) will stuck
> while searching POIs or Adresses. Today i changed the image to be load
> onto the device and created it from MapSource instead the one build by
> mkgmap. The functionality is better, but even not 100%. My question for
> now is, is there a possibility to extract the index data out of the img
> File to check it on the PC and eventually modify the data ?
> _______________________________________________
> mkgmap-dev mailing list
> mkgmap-dev at lists.mkgmap.org.uk
> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev

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