[mkgmap-dev] [PATCH] RoadMerger reverses roads

Sun Jan 12 14:57:06 GMT 2014

Hi Andrzej,
> 
> Isn't a bigger problem there?
> 
> The situation is that single OSM way creates multiple Garmin ways. This 
> could be done by copying OSM way or by referencing OSM way for new 
> Garmin object. Both variants can cause problems.
> 
> If there is a copy, then it could be processed differently, for example 
> when simplifying. And I think routable roads are processed different 
> than non-routable. This would lead to misalignment for Garmin objects.
> 
> If a new object uses a reference, then there will be problems like with 
> reversing. And any other processing of OSM way can lead to some problems 
> too.

since r2435 mkgmap always creates copies of the list with the point 
references, so that reversing of one copy doesn't influence the other copies.

On the other hand, the routines that remove points (short-arc-removal with value
>0 or the wrong-angle-handling in the high-prec-branch)
make sure that the changes are applied to the copies as well,
and this is done by overwriting the list of points again.

> 
> Multiplying of Garmin objects is done by "continue" statement in object 
> definition. I'm not sure, how this is processed internally in mkgmap, 
> probably it is using a reference. Maybe would be helpful if we could 
> select if there should be copy or reference for Garmin object? For 
> example there could be a statement like "continue_with_copy".
What problem do you want to solve with that? Should it reduce memory needs?

Gerd

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