[mkgmap-dev] Still problems with lakes

Sun Sep 23 08:54:44 BST 2012

Hello Henning,

> Sonds like an easy workaround without to much data, which have to 
> cached. A manual list would be a good thing, because mainly you as a 
> user know, which polygons are problematic.

I like the idea of a list, however it is produced. I wanted to create the list
automatically, but it was too big because of false candidates.
As long as no one finds an effecient and correct algorithm to create the list in 
splitter, we can at least use it to produce correct output in splitter and to 
verify that mkgmap produces good maps with it. 
The last point is quite important: mkgmap contains a lot of routines to handle 
incomplete or wrong or redundant data. That makes it very difficult 
to verify wether a change in splitter is producing better maps.

> 
> Maybe mkgmap could throw out a csv-list of each polygon and 
> multipolygon, which is causing problems.

I am not sure if mkgmap really detects all ids that cause problems. I
think it can't do that if the problem is a missing relation (in one tile), but maybe 
mkgmap sees the same relation id again in other tiles and reports it then.

> 
> r<id>, <link to object > (for mp)
> w<id>, <link to object> (for p)
> 
> So the user could have a view to the polygon and could start after 
> checking the list a second run.

Well, dependent on the input I expect the list can contain thousands of ids, so I doubt that 
you will want to look at that.

> 
> Of course it won't help, if you don't use a fix areas.list

Hmm, as long as the input files dont change, splitter will always produce the 
same areas.list, so I see no big problem here. It doesn't harm if the list of 
problematic ids contains a few ids that are no longer problematic, as long as it 
is complete. The automatic algorithm that I implemented creates a complete list,
but that list contains too many false entries (I guess the ratio is something like 
1:100 (100 false entries for one really problematic id) 

> 
> Also wo could start a wiki-page and collect problematic objects.
> 
> Henning

Thanks for the feedback. I'll try coding a few changes (e.g. filtering by tags), if 

that doesn't work out, I'll code the handling of a external list and we'll see what it helps.

Gerd

> Am 21.09.2012 14:59, schrieb toc-rox:
> > If a list with the IDs of all huge polygons is helpful, such a list could
> > perhaps created by
> > - user (manually)
> > - mkgmap (automatic)
> >
> > Regards Klaus
> 
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