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[mkgmap-dev] [PATCH v1] LocationHook speedup

From Gerd Petermann gpetermann_muenchen at hotmail.com on Sat Dec 31 14:04:15 GMT 2011

Hi WanMil,


> Date: Sat, 31 Dec 2011 14:55:08 +0100
> From: wmgcnfg at web.de
> To: mkgmap-dev at lists.mkgmap.org.uk
> Subject: Re: [mkgmap-dev] [PATCH v1] LocationHook speedup
> 
> Am 31.12.2011 14:51, schrieb Gerd Petermann:
> > Hello WanMil,
> >
> >  > admin_level=7 just an example. admin_levels are used differently in
> >  > countries and in regions etc.
> >  >
> >  > > I see
> >  > > "Verbandsgemeinde Waldmohr"
> >  > > http://www.openstreetmap.org/browse/relation/897709
> >  > > which is the only boundary that has admin_level=7. The interesting
> > thing is:
> >  > > the returned result-list for this boundary is always empty. So,
> > maybe there
> >  > > is a cheaper way to detect this first or does it means that there
> > is a bug
> >  > > in quadtree or the selection of the boundaries?
> >  >
> >  > Sounds more like a bug! But it's also possible that the higher
> >  > admin_levels (8,9,10,11) references all other admin_levels and therefore
> >  > there all elements of Waldmohr have been removed before querying for it.
> >
> > hmm, I think you missed the point that we start with lower admin_levels:
> > // Reverse the sorting because we want to start with the lowest admin level
> > Collections.reverse(boundaries);
> 
> No, I didn't. I should have better written admin_levels (11,10,9,8) but 
> the meaning is the same.
No, not really. We check 2,4,5,6 first.

> 
> >
> > and I found Waldmohr because it prevented the elements from being "fully
> > worked out".
> 
> Sounds reasonable. But then querying for Waldmohr should have returned 
> some elements, shouldn't it?
No, all elements are kept in the quadtree because they are not "fully worked out" until this admin_level=7 part is done, or to be more precise, until they are processed for admin_level=8 or higher, because for admin_level=7 nothing is changed in this special case.

Gerd

 		 	   		  
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