[mkgmap-dev] special case where splitting fails without a log message

Tue May 25 16:56:43 BST 2021

Hi Ticker,

with the attached patch ShapeMerger avoids to produce shapes where more than the start point is visited twice.
This produces much larger img files (even larger than trunk) but PolygonSplitter doesn't complain.

I have to find out what GpsMapEdit means with "has a jitter". Maybe only those are problematic.

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, 25. Mai 2021 14:00
An: Development list for mkgmap
Betreff: Re: [mkgmap-dev] special case where splitting fails without a log message

Sorry - sea.zip!

On Tue, 2021-05-25 at 12:36 +0100, Ticker Berkin wrote:
> Hi Gerd
>
> I'm getting very confused by this. When I build with my trunk (some
> filter order changes + a few others), I see a whole lot more that
> JOSM
> shows. It and your 6324001.img just show a central bit. Looking with
> GPSMapEdit with "Highlight Polygon Contours". I also see areas where
> all islands are inverted.
>
> I'll undo my trunk changes and look again.
>
> Does JOSM have self-intersection checking?
>
> Was the gpx trace hi-res (30bit) and then this kept when generating
> the
> osm. If not, then I'd expect problems.
>
> Ticker
>
>
> On Tue, 2021-05-25 at 11:18 +0000, Gerd Petermann wrote:
> > Hi Ticker,
> >
> > I didn't investigate the details. I've created the osm data by
> > converting a gpx back to osm. I guess in the original input
> > duplicate
> > points are identical. I found more such cases where parts are
> > removed.
> >
> > 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, 25. Mai 2021 12:51
> > An: Development list for mkgmap
> > Betreff: Re: [mkgmap-dev] special case where splitting fails
> > without
> > a log message
> >
> > Hi Gerd
> >
> > OK - I've reproduced this. Is split-failed.osm self-intersecting?
> > I'm
> > not sure how to tell from Josm, but it looks like it isn't. I get
> > the
> > messages from shapeSplitter because it thinks it is and then the
> > result
> > is not good - as expected.
> >
> > I'll investigate more.
> >
> > Ticker
> >
> >
> > On Tue, 2021-05-25 at 10:04 +0000, Gerd Petermann wrote:
> > > Hi Ticker,
> > >
> > > while looking at the problems with sea I found this case where
> > > ShapeSplitter removes a small part of an island from a self
> > > -intersecting polygon in res 24.
> > > Compiled with mkgmap from trunk, default style and no options.
> > >
> > > Look at 67.6742611, 14.6783525
> > >
> > > Found this with some check code that compares the area of the
> > > original polygon with that of sum of the parts.
> > >
> > > Gerd
> > > _______________________________________________
> > > mkgmap-dev mailing list
> > > mkgmap-dev at lists.mkgmap.org.uk
> > > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
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> > mkgmap-dev at lists.mkgmap.org.uk
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> > mkgmap-dev mailing list
> > mkgmap-dev at lists.mkgmap.org.uk
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