[mkgmap-dev] [PATCH v1] LocationHook speedup

Mon Jan 2 19:56:57 GMT 2012

Hello WanMil,

OK, I'll first try the effect by hard coding the wanted boundary list. If I really see a big improvement, I know how much complexety the new function can have. My first approach was to use subtract() for the Areas that are in the level=7 boundary, but that it much too slow.

Ciao,
Gerd

> Date: Mon, 2 Jan 2012 20:40:32 +0100
> From: wmgcnfg at web.de
> To: mkgmap-dev at lists.mkgmap.org.uk
> Subject: Re: [mkgmap-dev] [PATCH v1] LocationHook speedup
> 
> Hi Gerd,
> 
> good idea! I am not sure if this additional preprocessing information 
> has a great effect but it's worth trying that.
> 
> Up to now we don't have such a function. The place for such a function 
> would be to extend the BoundaryPreparer.workoutBoundaryRelations method.
> 
> WanMil
> 
> > Hello WanMil,
> >
> > I think I understand now what is so special with these admin_level=7
> > boundaries.
> > They form a collection of admin_level=8 boundaries. So, after working
> > through all admin_level=8 boundaries, the admin_level=7 is also done
> > because the admin_level=8 boundaries have the lies_in tag for them, but
> > LocationHook doesn't recognize that and continues to work through the
> > admin_level=6 boundaries. For each of the level=6 boundaries we retrieve
> > a large number of elements from quadTree, and most of them are already
> > fully worked out.
> > So, if I got this right, we could save a lot of time if we can detect
> > that admin_level=7 should not be added to remainingLevels which would
> > reduce the size of the quadtree earlier.
> > I think we would need a function that determines if a boundary x is
> > completely overlaped by boundaries with a higher admin_level that have
> > the lies_in for x.
> >
> > Does that make sense?
> > Do we have such a function?
> >
> > Gerd
> >
> >
> >  > > > >
> >  > > > > 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.
> >
> >
> >
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> 
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