Performance of map on device is drastically improved you you kick out those tiny polygons. Especially in cities where people have detail mapped all buildings. If you don't have building=yes or building=* in your style - then you can likely live with the filter disabled (not sure how much bigger the map data gets).
On Tue, 28 Jan 2020 at 21:41, Gerd Petermann < [email protected]> wrote: > Hi Mike, > > "sea" is build from shapes (= polygons). > The size filter is not explained in the style manual, but in the options > --min-size-polygon and --polygon-size-limits. > Unfortunately the filter works a bit unpredictable at low resolutions, so > in my eyes it is a good idea to disable. > I've never fully understood the purpose of this filter. I think it should > improve performance, but it seems to decrease quality even more. > > You may play with --min-size-polygon=0 to see what happens when the filter > is disabled. > > Gerd > > ________________________________________ > Von: Mike Baggaley <[email protected]> > Gesendet: Dienstag, 28. Januar 2020 21:21 > An: 'Gerd Petermann'; 'Development list for mkgmap' > Betreff: RE: [mkgmap-dev] Squaring off of land outlines > > Brilliant! A big improvement! It still doesn't exactly match the land > polygon, but that doesn't matter for my purposes. I suggest changing the to > do list so it says use the same algorithm for shapes, lines and sea. I also > suggest adding a sentence to the style manual in the explanation of > mkgmap:skipSizeFilter - the description doesn't explain the purpose or what > the effect is of passing the size filter. > > Thanks for your assistance, > Mike > > -----Original Message----- > From: Gerd Petermann [mailto:[email protected]] > Sent: 28 January 2020 19:03 > To: Mike Baggaley <[email protected]> > Subject: AW: [mkgmap-dev] Squaring off of land outlines > > Hi Mike, > > some small rather small sea polygons are filter by the size filter. > Change the statememnt for sea polygons to this: > natural=sea {add mkgmap:skipSizeFilter=true; name '${name}'} [0x32 > resolution 14] > > See also the corresponding rule in the default style: > natural=sea {add mkgmap:skipSizeFilter=true; set mkgmap:drawLevel=2} [0x32 > resolution 10] > > Gerd > > ________________________________________ > Von: Mike Baggaley <[email protected]> > Gesendet: Dienstag, 28. Januar 2020 19:39 > An: 'Gerd Petermann' > Betreff: RE: [mkgmap-dev] Squaring off of land outlines > > Thanks Gerd. I has been considering trying to find the problem myself, but > I'm not familiar with the writing sections of code, and they are > complicated > to get to grips with. > > Cheers, > Mike > > -----Original Message----- > From: Gerd Petermann [mailto:[email protected]] > Sent: 28 January 2020 16:16 > To: Mike Baggaley <[email protected]>; 'Development list for mkgmap' > <[email protected]> > Subject: AW: [mkgmap-dev] Squaring off of land outlines > > Hi Mike, > > okay, I'll have a closer look now. > > Gerd > > ________________________________________ > Von: Mike Baggaley <[email protected]> > Gesendet: Dienstag, 28. Januar 2020 16:51 > An: 'Gerd Petermann'; 'Development list for mkgmap' > Betreff: RE: [mkgmap-dev] Squaring off of land outlines > > Hi Gerd, the problem I have is not the one in the to do list. If I add the > polygon fill for natural=coastline, this does produce a different outline > than the one for the line, but both are reasonable approximations and > neither contains unexpected artefacts. The sea generation approximation is > wildly different and contains unwanted artefacts. Please see the attached > image that contains land in brown, sea in blue and an area of white that is > not filled by either. I believe this is a bug in the sea generation code. I > would expect sea generation to use the same algorithm as for filled areas > so > that holes are not left. I'm not too worried about the line being slightly > different. > > Regards, > Mike > > -----Original Message----- > From: Gerd Petermann [mailto:[email protected]] > Sent: 28 January 2020 14:59 > To: Mike Baggaley <[email protected]>; 'Development list for mkgmap' > <[email protected]> > Subject: AW: [mkgmap-dev] Squaring off of land outlines > > Hi Mike, > > See last point in the todo list: http://www.mkgmap.org.uk/dev/todo > I think what you see is exactly the result of the two different algos. > I can only suggest to omit the rendering of polygon outlines at resolutions > below 24. > > ________________________________________ > Von: Mike Baggaley <[email protected]> > Gesendet: Dienstag, 28. Januar 2020 15:23 > An: 'Gerd Petermann'; 'Development list for mkgmap' > Betreff: RE: [mkgmap-dev] Squaring off of land outlines > > Hi Gerd, I have produced a small sample which demonstrates the problem. It > contains one very small island. I have cut down the style to a bare minimum > with just two resolutions: 24 and 14 containing just sea and a coastline > outline. At resolution 24 the sea and coastline are coincident. At 14, they > are wildly different. The coastline at low resolution includes a spur which > is a complication. The ideal sea boundary would be the same as the > coastline, but with the spur removed (or perhaps the spur should not be on > the coastline either). I have included the style, typ file, command line in > a batch file and osm data in the attached zip. Please let me know if you > need anything else. > > Cheers, > Mike > > -----Original Message----- > From: Gerd Petermann [mailto:[email protected]] > Sent: 28 January 2020 08:26 > To: Mike Baggaley <[email protected]>; 'Development list for mkgmap' > <[email protected]> > Subject: AW: [mkgmap-dev] Squaring off of land outlines > > Hi Mike, > > I can try to find out what's wrong but I would need a lot more details > about > your map creation process. Could be an error in mkgmap or in the OSM data > or > in the --levels option or in the --min-size-polygon option or > --polygon-size-limits or ... > > Gerd > > ________________________________________ > Von: mkgmap-dev <[email protected]> im Auftrag von > Mike > Baggaley <[email protected]> > Gesendet: Montag, 27. Januar 2020 19:07 > An: 'Development list for mkgmap' > Betreff: Re: [mkgmap-dev] Squaring off of land outlines > > HI Gerd, I don't have an old map, but this has been happening for some time > - I am not sure whether it has always done this, but thought it would be > worth trying a few old versions to see whether it is bug that got > introduced, or is one that has always been there. It looks similar to the > problem reported on Feb 18 2017 with "Terraced/pixellated coastline with > --precomp-sea" as the title. I am not using --precomp-sea, but the problem > I > am getting is also in the sea outline. NopMap indicated that his problem > was > fixed in r3819, however, I have downloaded the source to that version and > compiled it, and it exhibits the same problem for me. > > Regards, > Mike > > -----Original Message----- > From: Gerd Petermann [mailto:[email protected]] > Sent: 27 January 2020 08:36 > To: 'Development list for mkgmap' <[email protected]> > Subject: Re: [mkgmap-dev] Squaring off of land outlines > > Hi Mike, > > I am not aware of a folder that keeps all older releases or an error that > would be related to this. > Are you sure that you didn't change mgkmap options like --levels or the > style or the typ file? > Do you still have a map which looks better? In that case you should find > the > string mkgmap in the img file, e.g. "mkgmap-r4431" > > Gerd > > > ________________________________________ > Von: mkgmap-dev <[email protected]> im Auftrag von > Mike > Baggaley <[email protected]> > Gesendet: Montag, 27. Januar 2020 01:43 > An: 'Development list for mkgmap' > Betreff: [mkgmap-dev] Squaring off of land outlines > > Hello, > > I am getting squaring off of the outline between land and sea at low zoom > levels (less than 16) - see attached BaseCamp images of Gran Canaria at > resolution 16 and at resolution 14 displayed at the same size. Obviously > some reduction in accuracy is expected at lower zoom level, but not these > artefacts. I'm not sure when this started happening but believe it was some > time ago. I can't seem to find the old releases to try previous versions, > http://svn.mkgmap.org.uk/mkgmap/releases/ just shows me an empty folder. > Can > you point me to the correct download folder that contains the previous jar > files, and/or let me know if this is a known problem, and if so whether > there is a workaround? > > Thanks, > Mike > > > _______________________________________________ > mkgmap-dev mailing list > [email protected] > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > _______________________________________________ > mkgmap-dev mailing list > [email protected] > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > -- Felix Hartman - Openmtbmap.org & VeloMap.org Schusterbergweg 32/8 6020 Innsbruck Austria - Österreich
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