[mkgmap-dev] Terraced/pixellated coastline with --precomp-sea

Mon Feb 20 05:10:42 GMT 2017

Hi NopMap,

Both precompiled and generated sea will produce polygons with
natural=sea or natural=land
by default, so your style probably contained a rule for one of them.

With r3815 I've fixed one error regarding skipSizeFilter . I tried to reproduce your problem
with r3814 by changing the default style to use 0x3c for natural=sea and found no problem unless
I used an extreme value for the size filter like --min-size-polygon=300.
Please check your options  for this filter, see output for
java -jar mkgmap.jar --help:options
It shows:
--min-size-polygon=NUM
        Removes all polygons smaller than NUM from the map.
        This reduces map size and speeds up redrawing of maps.
        Recommended value is 8 to 15, default is 8.
        See also polygon-size-limits.

--polygon-size-limits=limits code
        Allows to specify different min-size-polygon values for each resolution.
        Sample:
        --polygon-size-limits="24:12, 18:10, 16:8, 14:4, 12:2, 11:0"
        If a resolution is not given, mkgmap uses the value for the next higher
        one. For the given sample, resolutions 19 to 24 will use value 12,
        resolution 17 and 18 will use 10, and so on.
        Value 0 means to skip the size filter.
        Note that in resolution 24 the filter is not used.

If these settings are extreme you should see problems with all large polygons.

Hope this helps.

Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von NopMap <ekkehart at gmx.de>
Gesendet: Sonntag, 19. Februar 2017 20:51:51
An: mkgmap-dev at lists.mkgmap.org.uk
Betreff: Re: [mkgmap-dev] Terraced/pixellated coastline with --precomp-sea

Hi Gerd,

Gerd Petermann wrote
> The default style contains this line:
> natural=sea { add mkgmap:skipSizeFilter=true; set mkgmap:drawLevel=2 }
> [0x32 resolution 10]
>
> which in fact tells mkgmap to skip the size filter for the polygons
> generated by precomp-sea.

Thank you, that was the missing key information. My custom style does not
contain any such line. After adding a similar rule to my style, I was able
to get proper sea areas.

But I was forced to use the 0x32 area like in your example. It was unused in
my style and I never had a rule for it. First I tried 0x3C which I used for
all large water bodies - including the generated sea polys - in the past,
but then the sea polygons were disappearing again. It seems that multiple
rules leading to the same Garmin object are somehow connected and the
skipSizeFilter is somehow cancelled.

I still do not understand why --generate-sea has worked without any rule
like the one you posted and without using 0x32 for years, as long as the sea
polys were generated from OSM data. Shouldn't the sea generator's output be
the same, regarless of the source of input?

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