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

From Felix Hartmann extremecarver at googlemail.com on Thu May 27 12:07:42 BST 2010

On 27.05.2010 13:00, Johann Gail wrote:
>>> Only solution I think is to make --route default and
>>> compulsory for the moment. Else people will create maps that havoc other
>>> maps without realising.
>> I strongly advice against this. The problem has been around a very long time
>> and nobody noticed, so I don't think it is that critical. The workaround is
>> simple: Do not use the latest version of MS/BC until the problem is fixed.
>> On the other hand, routable maps seem to be much larger than non-routable
>> maps. If you change the behaviour of mkgamp there you can break things by
>> enlarging the maps so they do not fit into the memory they used previously.
>> If the map is tailored to fit an 1GB SD card, it will no longer. There are
>> older devices that have a limited amount of built-in memory and you might
>> make maps unusable that now are fitting into the devices.
>> In short: I think a compulsory change would break more than it helps right
>> now.
> Felix, I appreciate your detailed work in investigate this bug, which
> will concern  mkgamp in the future. But at the moment it is not known,
> where this NOD-Bit resides, so we can not do a clean solution.
> As you have shown with your detailed work, there is a simple workaround.
> If you want universal non-routable maps, then delete the routing
> specific entries from the style file and set the --route option.
> Therefore it *IS* an option, to be able for each user to fulfill their
> own needs. There is no need to make this mandatory.
> Ok, I admit it is a little confusing at the moment to need to set the
> --route option to generate a working nonroutable map for the future
> version of MS, but I think it is only a matter of time, until mkgmap
> handles the flag correctly. If in future the problem will become a
> bigger one, for sure someone wil look for a solution. At the moment
> there is simply no urgent need.
I wouldn't say it is not urgent. I got reports from Oregon 3.80 Firmware 
users, that they already have problems with autorouting if they have 
"nonroutable" mkgmap created maps on their GPS. The biggest problem is, 
people will think the routable map is at fault, while the nonroutable 
cause all the trouble.
The least to do would be to change mkgmap behaviour to write an empty 
NOD index if --route is NOT given (so people don't have to fiddle with 
their styles).
I had a testunit based on newer firmware and it wouldn't even start 
anymore until I removed the SD-Card after having calculated a route that 
caused the GPS to crash. And 6.16.1 is not a future version of 
Mapsource, but since 3 weeks the current stable version. Basecamp is 
affected since 3.0.2 (~5 weeks old) already.
And we can't expect people to have a parallel installation of older 
Mapsource/Basecamp (while in practice without this bug, 6.16 and 
Basecamp 3 feature autorouting that works at least twice better in 
comparison with older versions).
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