[mkgmap-dev] More method options for is_in function

Tue Feb 11 09:05:21 GMT 2020

Hi Gerd

It's important to handle the polygons as merged for the LINE and
POLYGON processing, so that internal splitting by multi-polygon
processing doesn't affect the answer relating to ON queries. For
overlapping polygons, however, the ON query is ambiguous and I'm not
sure how much effort it is worth taking to resolve it with respect to
the edges of one polygon that are within the other.

I've just seen your next posting.

For POINTs: I agree, much the same as above applies to the ON query.

So, we need to decide on the policy for ON queries relating to the OSM
defined edges of one polygon within another polygon, or just ignore the
issue on the grounds that the situation is unlikely and it is an arbitr
ary decision anyway.

Ticker

On Tue, 2020-02-11 at 08:31 +0000, Gerd Petermann wrote:
> Hi Ticker,
> 
> my understanding is that is_in(.., 'on') returns true if the point is
> on the boundary, not in or out.
> With line and polygon rules we merge overlapping polygons before we
> test, so I tried to do something similar with points.
> 
> Gerd
> 
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> von Ticker Berkin <rwb-mkgmap at jagit.co.uk>
> Gesendet: Dienstag, 11. Februar 2020 09:24
> An: Development list for mkgmap
> Betreff: Re: [mkgmap-dev] More method options for is_in function
> 
> Hi Gerd
> 
> Yes, overlapping polygons was the case I was thinking about. I'd say
> that is_in(.., 'on') should be true if ON the edge of one, regardless
> of being IN the other.
> 
> Can you commit my last change and then, if you are not changing
> IsInUtil at the moment, I'd like to move some of the code around.
> I'll
> also start some documentation for the Style Manual.
> 
> Ticker
> 
> On Mon, 2020-02-10 at 18:48 +0000, Gerd Petermann wrote:
> > Hi Ticker,
> > 
> > reg. POINT is_in(..., 'on') : You think about the case that a point
> > is inside one polygon and on boundary of another? Should not happen
> > with correct OSM data but the question is also what result you want
> > to get.
> > reg. isComplete():
> > This is about input data where not all coords are known and thus
> > the
> > geometry of the way is undefined. Should never happen with normal
> > input.
> > I am not sure but I think splitting at tile borders did not yet
> > happen with the polygons, only the preparation is done by adding
> > nodes at the tile border.
> > 
> > Gerd
> > 
> > ________________________________________
> > Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> > von Ticker Berkin <rwb-mkgmap at jagit.co.uk>
> > Gesendet: Montag, 10. Februar 2020 18:09
> > An: Development list for mkgmap
> > Betreff: Re: [mkgmap-dev] More method options for is_in function
> > 
> > Hi Gerd
> > 
> > I've re-implemented the POINT test within IsInFunction, using the
> > stopping methods etc, which are now coded, but only relevant for
> > this
> > context at the moment. This implementation has other advantage in
> > that
> > the method can control the onBoundary condition. Also the logic in
> > calcInsideness can give the wrong answer for POINT is_in(...,
> > 'on').
> > 
> > I didn't want to change IsInUtil while you are working on it and
> > I'm
> > not sure yet of the best way to handle the LINE/POLYGON versions.
> > 
> > There are a couple of aspects of these that occur to me:
> > 
> > It would be clearer to test for kind=POINT/LINE/POLYGON etc rather
> > than
> > el instanceof.
> > 
> > w.isComplete():
> > - Will this will cause different answers depending on tile
> > splitting,
> > or is the complete polygon represented; even the bits outside the
> > tile?
> > - The ANY methods should be processed and will be correct.
> > 
> > Thanks for spotting my error with tstMethod.
> > 
> > This patch also improves the method error message; listing the
> > possible
> > methods for the context.
> > 
> > Ticker
> > 
> > On Mon, 2020-02-10 at 13:14 +0000, Gerd Petermann wrote:
> > > Hi all,
> > > 
> > > see
> > > http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4
> > > 44
> > > 2
> > > 
> > > @Ticker:
> > > I assume you are working on an alternative implementation of the
> > > methods in IsInUtil?
> > > If not I'd like to remove all the code duplication introduced
> > > with
> > > the last patch.
> > > 
> > > Gerd
> > > _______________________________________________
> > > mkgmap-dev mailing list
> > > mkgmap-dev at lists.mkgmap.org.uk
> > > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
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