[mkgmap-dev] mkgmap-dev Digest, Vol 153, Issue 40 Resolution 23 raster problems

Wed Apr 28 13:58:15 BST 2021

Oh I thought it was mainly meant for contourlines. Did not know you intend
it to be used in general. I am not really sure how and where to check for
quality.

On Wed, 28 Apr 2021 at 20:13, Gerd Petermann <
gpetermann_muenchen at hotmail.com> wrote:

> Hi Felix,
>
> your screen shots only show contour lines but the patch works on all types
> of lines and polygons. So, please also check the results with other maps.
>
> Gerd
>
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von
> Felix Hartmann <extremecarver at gmail.com>
> Gesendet: Mittwoch, 28. April 2021 04:54
> An: Development list for mkgmap; Andrzej Popowski
> Betreff: Re: [mkgmap-dev] mkgmap-dev Digest, Vol 153, Issue 40 Resolution
> 23 raster problems
>
> forgot 1.3 value - that is good enough (and this location is not the most
> difficult, but there are very few places that are worse. So I feel it's
> good enough as if it's fine here - there are very very few other places
> that are still problematic.
>
>
> On Wed, 28 Apr 2021 at 10:50, Felix Hartmann <extremecarver at gmail.com
> <mailto:extremecarver at gmail.com>> wrote:
> Thanks for that patch, the improvement is not as big as from the previous
> patch - but there is some.
> I analysed it a bit more - and I think there needs to be one more change -
> actually in general and not only for contourlines.
>
> We need different values for the douglas peucker algorithm depending on
> resolution!
>
> Right now we can only set one value, and that is multiplied for each
> resolution?
> Based on the current state I would like to have
>
> resolution
> 24= 0.0 or maybe actually have it active at 24 as well trying a value of
> 0.3 or so. Where there any problems with autorouting or why is it not
> possible to use it at resolution 24 as well?
> 23=1.3
> 22=2.6
> 21=3.9
> 20-11=5.4
>
>
> Especially if we produce a map without resolution 24, then resolution 23
> needs to have much lower DP value than the subsequent resolutions. Using
> 1.3 for resolution 23 makes the quality IMHO good enough to be used for an
> contourlines only map for GPS devices and skipping resolution 24
> altogether. For Desktop use resolution 24 may still make sense for
> contourlines - but even then the difference is only in very steep areas.
>
> Attached some screenshots at resolution 24, and at 23 with different DP
> values and one of patch2.
>
> On Tue, 27 Apr 2021 at 23:16, Andrzej Popowski <popej at poczta.onet.pl
> <mailto:popej at poczta.onet.pl>> wrote:
> Hi,
>
> some more experiments, see attached patch. I have tried to optimize
> rounding of coordinates for lowest distance to line. This is not good
> for polygons, because can creates gaps between adjacent polygons.
>
> --
> Best regards,
> Andrzej
> _______________________________________________
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>
>
> --
> Felix Hartman - Openmtbmap.org & VeloMap.org
>
>
>
> --
> Felix Hartman - Openmtbmap.org & VeloMap.org
>
> _______________________________________________
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> mkgmap-dev at lists.mkgmap.org.uk
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>

-- 
Felix Hartman - Openmtbmap.org & VeloMap.org
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