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[mkgmap-dev] Really Serious bug when not using --route

From Felix Hartmann extremecarver at googlemail.com on Mon May 24 19:50:50 BST 2010

On 24.05.2010 18:01, Christian Gawron wrote:
> Maybe it's this bit in the TDB-Header (HeaderBlock.java):
>            os.write(1);    // map is routable
> At least it looks strange that this bit is set regardless of the 
> --route option, and there are similar flags related to DEM info in 
> this block as well ...
> Best wishes
> Christian
You mean setting os.write(0); // map is nonroutable should fix it??
I'll give it a go and try it out. It's definitely better unsetting it 
than inserting an empty NOD table (which is however much much better 
than having an index point to it, and then the NOD table not found at 
all, and seriously affecting other maps).
> Felix Hartmann schrieb:
>> On 23.05.2010 18:24, Felix Hartmann wrote:
>>> There is a serious bug that breaks routable maps when --route is NOT 
>>> given. This bug will in future break routing on most GPS devices and 
>>> is already inflicting Mapsource 6.16.1 and Basecamp 3.
>>> This means that also if you compile maps that are not routable, you 
>>> have to pass the --route parameter. Else the GPS / Mapsource looks 
>>> into an empty NOD table and may crash. This will happen as soon as 
>>> you mix routable maps with the non routable mkgmap created maps.
>>> The problem is that Mapsource and the GPS search for 63440000.NOD 
>>> data (63440000 as an example placeholder for the mapname). 
>>> "Falagar", a developer at Garmin said to release a fix for this bug 
>>> in Mapsource 6.16.2 however mentioned that this fix will not be 
>>> carried on to GPS devices and will still mean a deterioration of 
>>> overall routing.
>>> I'm not sure what the exact problem for this is (I just tried even 
>>> very old mkgmap versions like 858 and also there the problem arises) 
>>> but currently this means that --route should be the compulsory for 
>>> all map creation, also not routable ones. If you have old maps (eg 
>>> transparent contourline maps) that are troublesome to rebuilt, then 
>>> opening with gpsmapedit, saving as mp and recompiling passing 
>>> --route parameter is enough to solve the problem.
>>> I think that until the bug is found, mkgmap should adopt --route as 
>>> standard, because it may happen that if users put an mkgmap created 
>>> without --route onto their GPS besides other routable maps, these 
>>> maps might impact autorouting for the other routable maps (except if 
>>> "deactivated" on the GPS).
>> Just as an update. I got the following answer from Falagar, 
>> concerning creating all maps with --route parameter:
>> /Naja, das ist halt nur ein Trick. Am besten waere es, die NOD-Flag 
>> zu entfernen, aber ich weiss nicht, ob ihr wisst, wo die ist. Ich 
>> weiss es leider auch nicht.
>> Es koennte evtl. ein wenig langsamer sein, wenn MS & Geraet die 
>> Routinginformationen erst oeffnen muessen, bevor wir feststellen, 
>> dass da keine Info drin ist.
>> Aber ich denke, das sollte erst einmal funktionieren. /
>> Translation. This is only a trick. Best would be to completly remove 
>> the NOD-Flag, but I don't know whether you know where it is. 
>> Actually, I don't know it either.
>> Eventually it could be a little bit slower if Mapsource & GPS first 
>> has to open the routing information, until it notices that there is 
>> no info inside.
>> But I think this would do if for a beginning.
>> So either someone finds the NOD flag (gmaptool also knows nothing 
>> about it, removing NOD data with gmaptool does not clear the NOD 
>> flag, ) and it will be deactivated when --route is not given, or we 
>> pass --route as mandatory, as we obviously miss something in the 
>> implementation. I will give some really old versions a go to see if 
>> they did it correctly and the bug got introduced with the advent of 
>> routing in mkgmap, and send a message if they worked correctly. If 
>> not then we probably set this flag since the beginning (but until 
>> recently this was no problem).
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