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

Fri Apr 23 12:44:40 BST 2021

I don't think this can be improved.

As I understand it, internally Garmin devices hold coordinates in the
number of bits specified in the level.

So 24 bits has a resolution of 2.4 metres, 23 bits has a resolution of 4.8
meters and so on. If you look carefully, all the vertices of the lines lie
on a square grid.

Having said that, that must be a very steep slope - unless something else
is creating the granularity.

On Fri, 23 Apr 2021 at 12:06, <mkgmap-dev-request at lists.mkgmap.org.uk>
wrote:

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>    1. Resolution 23 raster problems (Felix Hartmann)
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> ---------- Forwarded message ----------
> From: Felix Hartmann <extremecarver at gmail.com>
> To: Development list for mkgmap <mkgmap-dev at lists.mkgmap.org.uk>
> Cc:
> Bcc:
> Date: Fri, 23 Apr 2021 18:01:15 +0800
> Subject: [mkgmap-dev] Resolution 23 raster problems
> Any ideas why this is happening?
> Some of the contourlines intersect each other at resolution 23 - I
> especially used reduce-point-density=1.0 to try to stop it.
>
> java -jar -Xmx47000M /home/contourlines/mkgmap.jar --keep-going
> --dem-poly=/home/contourlines/bounds/bayern.poly
> --series-name=openmtbmap-cntrs-DBY-23-Apr-2021
> --dem=/home/contourlines/hgt/VIEW1/,/home/contourlines/hgt/SRTM1v3.0,/home/contourlines/hgt/VIEW3/,/home/contourlines/hgt/SRTM3v3.0/
> --dem-dists=5520 --max-jobs=7 --reduce-point-density=1 --transparent
> --style-file=srtm24 --latin1 95260000.osm.pbf
>
> Is there any way to improve this?
>
> Look at the screenshots - the small one is resolution 23, the big one 24.
> If using 10m interval contourlines this is pretty obviously not ideal.
> Resolution 24 could be nicer - but I guess this is more a problem of
> phyghtmap (while groundtruth can produce higher quality), but resolution 23
> really becomes confusing vs 24...:
> [image: Simplification_23.PNG]
> [image: Oiginal_24.PNG]
>
> If pictures don't show
> https://openmtbmap.org/23.PNG
> https://openmtbmap.org/24.PNG
> --
> Felix Hartman - Openmtbmap.org & VeloMap.org
>
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