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@lists.mkgmap.org.uk> wrote:
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Today's Topics:

   1. Resolution 23 raster problems (Felix Hartmann)



---------- Forwarded message ----------
From: Felix Hartmann <extremecarver@gmail.com>
To: Development list for mkgmap <mkgmap-dev@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...:
Simplification_23.PNG
Oiginal_24.PNG

If pictures don't show 
--
Felix Hartman - Openmtbmap.org & VeloMap.org

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