[mkgmap-dev] 4179

Mon May 17 15:02:24 BST 2021

The case was that many of those roads are created by continue. If the main
road is merged but the direction dependant road not - then at lower
resolutions the DP filter will create a mess. This is only relevant for 21
or lower I feel. 22-24 it's all right. Most overlays will be right in that
resolution. Even though I have loads of those overlays, luckily those that
are direction dependent are only in resolution 24 and 23. Some people may
have overlays at lower resolution however.

All lines created with continue at resolution lower 23 are problematic
concerning this matter. And because I have lots of overview - E.g. oneway
arrows, oneway streets are loads, there is quite a difference in map size
regarding oneway roads being merged from resolution 23 onwards or not. I
think it makes up for around 1.5% map size. The 1.5% is not the problem,
but that primary roads, highways and so on are usually mapped with two
lines, and each one has oneway attached. Then quite a bit of the
optimization is lost if those roads are not merged. As for me highways are
not routable, I just delete the oneway in style before processing... Could
skip that if non routable lines do not care for oneway. Same for railways
(and railways as well are displayed to quite a low resolution. Fixed by
deleting oneway for railway=* & highway!=*

On Mon, 17 May 2021 at 18:39, Andrzej Popowski <popej at poczta.onet.pl> wrote:

> Hi Felix,
>
> why don't make it simple?
>
> Routable roads with oneway=-1 have to be reversed.
> Non-routable lines with oneway=-1 have to be reversed if has-direction
> is present.
> If has-direction is present, road is not reversible for merging at all
> layers.
>
> I don't understand your suggestion for non-reversible road limited to
> some resolutions. I can't imagine what is the use of it, but maybe you
> have some example. Anyway, I see it like that:
> - there are rare cases for it if any,
> - even if the line remains non-reversible at all levels, there is not
> much difference for a whole map,
> - if you really need that kind of solution, you can create 2 different
> objects for different layers.
>
> --
> Best regards,
> Andrzej
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>

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