Hi Ticker, attached is my patch to fix the special case when partitioning cuts a multipolygon so that only two equal rectangles are left. This also fixes the problem for me, but I guess it might fail in edge cases where the cutting goes through a point where inner and outer diverge. Reg. your patch: Looks good, I would just rename NATURAL_TAG_KEY to TK_NATURAL so that it matches the naming in other sources. I am running some tests reg. precompiled sea at the moment... Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Gerd Petermann <gpetermann_muenchen@hotmail.com> Gesendet: Donnerstag, 12. Mai 2022 14:55 An: Development list for mkgmap Betreff: Re: [mkgmap-dev] generate-sea option and faster-mp changes Hi Ticker, I can reproduce the error with the old code and that error disappears when I disable the partitioning in class MultiPolygonRelation. I've not yet understood why, but I fear your patch simply works around this problem. The partitioning seems to produce parts where an inner and an outer rectangle both seem to cover the same area. I think I have to fix that as well. Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Ticker Berkin <rwb-mkgmap@jagit.co.uk> Gesendet: Donnerstag, 12. Mai 2022 14:29 An: Development list for mkgmap Betreff: Re: [mkgmap-dev] generate-sea option and faster-mp changes Hi Gerd Looking at older versions (2019), createLandWay() makes a polygon with the tile bounds; no extra. This hasn't changed since then. createSeaWay() has flag to enlarge the polygon slightly and use of this hasn't changed in the release version Ticker On Thu, 2022-05-12 at 08:37 +0000, Gerd Petermann wrote:
Hi Ticker,
thanks, I'll take a look at it. My understanding was that SeaGenerator should produce an outer way which is slightly larger than the tile. Did I change that?
Gerd
________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Ticker Berkin <rwb-mkgmap@jagit.co.uk> Gesendet: Donnerstag, 12. Mai 2022 08:20 An: mkgmap development Betreff: [mkgmap-dev] generate-sea option and faster-mp changes
Hi Gerd
I've just rebuilt britain-and-ireland-latest.osm.pbf with the current trunk and find that many tiles on the coast have flooded rectangles. The coastline is all correct and these flooded area are normally well inland and unrelated to where the coastline crosses the tile boundary.
I use option --generate-sea="multipolygon,extend-sea-sectors,close-gaps=750" and this worked fine up to about a year ago - I've only just noticed the problem.
Cutting this from a suitable area (Wales, UK, Britain, Europe etc)
74220030: 2408448,-331776 to 2430976,-196608 # : 51.679688,-7.119141 to 52.163086,-4.218750
and building with minimal options plus above and default style should demonstrate the problem. There are also extra error messages starting
... 030.osm.pbf: Multipolygon generated SeaPolygonRelation [nat...
in the log file, which I attach
I think it is related to the faster-mp changes and the MP structure SeaGenerator created. This has 1 outer (the tile) and all bits of land are inners, including land touching the edge of the tile.
I've attached a patch for an enhanced version of SeaGenerator that distinguishes between land/sea areas that touch the edge and true [anti-]islands and only use MP processing for the islands. With this, tiles are correct.
It also has other benefits: It is clearer in what is happening, doesn't do a lot of pointless tagging of ways that will joined to become polygons, etc
Ticker
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