[mkgmap-dev] [mkgmap-svn] Commit r4622: - use IsInUtil to do geometry calculations like insideness or outsideness: Allows to remove a lot of complex code but might be slower in some cases.

Thu Apr 1 12:24:00 BST 2021

I meant intersecting polygons

Ticker

On Thu, 2021-04-01 at 12:08 +0100, Ticker Berkin wrote:
> Hi Gerd
> 
> I agree that calcContains should be changed as you suggest.
> 
> My view otherwise is that the code should be as simple as possible
> for
> "correct" cases and not go to any trouble to detect overlapping
> polygons in this phase, but just allocate them as [outer {inner}]+
> and,
> if the cutting logic has problems during its processing, then it can
> flag errors.
> 
> Ticker 
> 
> On Thu, 2021-04-01 at 09:13 +0000, Gerd Petermann wrote:
> > Hi Ticker,
> > 
> > I think the big question is what the code is expected to do with
> > overlapping polygons. The code in trunk may or may not cut out an
> > inner ring that overlaps the outer. If I got that right it was
> > intended to ignore all rings which are overlapping, but I showed
> > that
> > this doesn't always work.
> > 
> > So, probably I should change the logic in the branch from
> > return (x & IsInUtil.IN) != 0;
> > to
> > return (x & IsInUtil.OUT) == 0;
> > 
> > Means, calcContains() would return false if at least one point is
> > not
> > contained.
> > 
> > Gerd
> > 
> > ________________________________________
> > Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> > von Gerd Petermann <gpetermann_muenchen at hotmail.com>
> > Gesendet: Donnerstag, 1. April 2021 10:16
> > An: Development list for mkgmap
> > Betreff: Re: [mkgmap-dev] [mkgmap-svn] Commit r4622: - use IsInUtil
> > to do geometry calculations like insideness or outsideness: Allows
> > to
> > remove a lot of complex code but might be slower in some cases.
> > 
> > Hi Ticker,
> > 
> > to be more prezise: Looking at the code in runIntersectionCheck()
> > it
> > may change the Bitset unfinishedPolys. Up to now I did not find a
> > case where this happens, so I am tempted to remove the code, but
> > I'd
> > feel better if I would understand why it was coded before removing
> > it.
> > 
> > Gerd
> > 
> > 
> > ________________________________________
> > Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> > von Gerd Petermann <gpetermann_muenchen at hotmail.com>
> > Gesendet: Donnerstag, 1. April 2021 09:29
> > An: Development list for mkgmap
> > Betreff: Re: [mkgmap-dev] [mkgmap-svn] Commit r4622: - use IsInUtil
> > to do geometry calculations like insideness or outsideness: Allows
> > to
> > remove a lot of complex code but might be slower in some cases.
> > 
> > Hi Ticker,
> > 
> > yes, that's what I plan to do. Right now I try to understand what
> > is
> > done with the data in collection intersectingPolygons.
> > 
> > Gerd
> > 
> > 
> > ________________________________________
> > Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> > von Ticker Berkin <rwb-mkgmap at jagit.co.uk>
> > Gesendet: Donnerstag, 1. April 2021 09:25
> > An: mkgmap-dev at lists.mkgmap.org.uk; mkgmap-svn at lists.mkgmap.org.uk
> > Betreff: Re: [mkgmap-dev] [mkgmap-svn] Commit r4622: - use IsInUtil
> > to do geometry calculations like insideness or outsideness: Allows
> > to
> > remove a lot of complex code but might be slower in some cases.
> > 
> > Hi Gerd
> > 
> > Wouldn't it be more efficient to choose a point within a each
> > polygon
> > and then use IsInUtils.isPointInShape and the relative areas to
> > test
> > if
> > this polygon is in others. The point could be the centre of the
> > polygon, after checking isPointInShape == IN on itself, and, if
> > not,
> > make do with the closing point, or some trial and error moving from
> > the
> > closing point.
> > 
> > This also bypasses ambiguities cause by overlapping polygons in
> > this
> > phase of the logic.
> > 
> > Ticker
> > 
> > On Wed, 2021-03-31 at 15:56 +0100, svn commit wrote:
> > > Version mkgmap-r4622 was committed by gerd on Wed, 31 Mar 2021
> > > BRANCH: faster-mp
> > > - use IsInUtil to do geometry calculations like insideness or
> > > outsideness: Allows to remove a lot of complex code but might be
> > > slower in some cases.
> > > - document the poor completeness of collection
> > > intersectingPolygons.
> > > Probably will removed as well.
> > > 
> > > 
> > > http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4
> > > 62
> > > 2
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