I kinda feel by default even oneway=yes should only mean do not change direction for level 0. If someone uses a style to have arrows showing the oneway, then only for that arrow line (defined by tag) the direction cannot be reversed. Yes the problem of DP filter rests - I feel this does not matter for resolution 24 and even 23, but if you display arrows for resolution 22 or higher then a tag should not merge the underlying lines. Besides rivers (then also many styles do not have an arrow for rivers, or you could decide to show the arrows only at resolution 24 and 23) few lines will be objection dependent.

I will try out now if there is any change in routing - but I will only write again if there unexpectedly is. The sharp angles changed routing for the better for my maps by quite a lot. So maybe with now some less lines being merged, there actually will be a little change for the worse back to the old behavior. Not sure..

On Thu, 13 May 2021 at 14:07, Gerd Petermann <gpetermann_muenchen@hotmail.com> wrote:

Hi Felix,

yes, size increases if your style sets mkgmap:has-direction=true. I just want to make sure that the direction flag is treated correctly first.
As already discussed we might introduce a new option or tag to tell mkgmap the min. level at which the direction has to be kept. You suggested to ignore direction at level > 0, I think it might depend on the style and TYP. I'll play with the OFM style to find out more.

The change should not affect routing at all (none of the changes in the low-res-opt branch should).

Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Felix Hartmann <extremecarver@gmail.com>
Gesendet: Donnerstag, 13. Mai 2021 02:59
An: Development list for mkgmap
Betreff: [mkgmap-dev] Commit 4710

fix error in LineMergeFilter reg. lines with direction
The line merger should not merge lines if one has the direction flag set and the other has not. Problem exists also in trunk.

Hmm fixing this stopped all the nice size optimization. Map size got much bigger again.
I did not find any place where this mattered. Routing was also not affected badly. Maybe I did not look good enough?

I do not see why not to merge them. As long as it`s not the opposite it seems fine...
Map size increase/decrease is around 1.5% with my style. So thats quite a big difference.
--
Felix Hartman - Openmtbmap.org & VeloMap.org

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