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<p>Hi Gerd</p>
<p>Have been checking a few garmin tdbs and it appears that <br>
</p>
<p>while the first 3 bytes remain the same for each, ie 01 00 00, <br>
</p>
<p>the last four bytes are always different and never zero !<br>
</p>
<p>also ,except with mkgmap tiles, I have not come across C3 in the
second byte ie a 01 <b>c3 </b>00 <br>
</p>
<p>Nick<br>
</p>
<br>
<div class="moz-cite-prefix">On 05/02/2018 08:36, Gerd Petermann
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:AM2PR08MB02926B1B029E7A125784D6339EFE0@AM2PR08MB0292.eurprd08.prod.outlook.com">
<pre wrap="">Hi,
Ive discussed with Frank if there might be a field in the tdb file that has to be changed.
Maybe there is a value that tells MapSource something about the alignment of DEM data?
I don't have a single original Garmin tdb file :-(
It seems that mkgmap writes some constants that might be important, e.g. MapDetailBlock.java contains
//01 c3 00 ff
os.write4(0xff00c301);
os.write(0);
os.write(0);
os.write(0);
The wiki [1] describes these 7 bytes as
"byte:0 has copyright text,byte 1: has 0x53 text : byte 2:if 1 then bytes 3_7: an unknown total (density) "
The display tool seems to expect something similar to the wiki:
d.rawValue(2, "01 01");
d.byteValue("intro flag");
d.intValue("intro %d");
Any idea what this "intro" or "unknown total(density) could be ?
And what is the 0x53 text?
[1]<a class="moz-txt-link-freetext" href="https://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin/TDB_File_Format">https://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin/TDB_File_Format</a>
Gerd
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</pre>
</blockquote>
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