I think merging would be fine. Garmin hates sharp angles anyhow and will likely not chose them for a car route. And if cycling or walking it doesn't matter too much if really an announcement is not given. Anyhow on sharp turns there is usually a turn announcement also on the same road - most switchbacks on trails are announced. Would be great if the penalty this way could be lowered a bit..
On Fri, 7 May 2021 at 16:35, Mike Baggaley <[email protected]> wrote: > Hi Gerd, > > I believe this activity is a precursor to reducing zig zags at low > resolutions (though I may be confusing two different activities). I think > the case shown here would be better handled by seeing whether at the low > resolution the two entry points to the A13 can be reduced to a single > point. > For each side of the junction we would have two coincident one-way roads > that could be reduced to a single two way road. Merging the two one-way > roads into one would prevent this from taking place. I was under the > impression that mkgmap split ways at junctions anyway, so I'm not sure what > would be gained by joining these together. I do not have a full > understanding of the code, so may have misunderstood this bit. > > Cheers, > Mike > > -----Original Message----- > From: Gerd Petermann [mailto:[email protected]] > Sent: 07 May 2021 08:55 > To: Development list for mkgmap <[email protected]> > Subject: Re: [mkgmap-dev] patch: improve RoadMerger: allow to merge roads > with reversed points > > Hi all, > > See e.g. the link roads which meat at > https://www.openstreetmap.org/node/606366325 > I really wonder how mkgmap should treat roads like that which build a sharp > angle. Current code doesn't merge them. I don't know how it worked in 2014 > but today I see no good reason for that. Routing results seem to be the > same > and mainly depend on the "avoid u-turn" setting. > Maybe there is a difference when the --ignore-sharp-angles is used, but > than > that's probably exactly what the user wants? > > I've also seen several places where the two link roads are mapped with a > single OSM way. > > The correct mapping probably requires two OSM ways and a turn restriction, > but the Garmin routing algo really doesn't like sharp angles anyway and > prefers large detours to avoid them when "avoid u-turn" is enabled. > > I've attached a new patch which ignores sharp angles where only two roads > meet. This gives a few more merges. > If you change the line > private static final double MAX_MERGE_ANGLE = 130.0; > to > private static final double MAX_MERGE_ANGLE = 180.0; > mkgmap will still prefer to merge the roads with the smallest angle but > will > also merge those with a sharp angle and thus reduce the NOD/NET size even > more. > > I think mkgmap should use always merge if --ignore-sharp-angles is used, > but that's not implemented yet. > > Gerd > > ________________________________________ > Von: mkgmap-dev <[email protected]> im Auftrag von > Gerd > Petermann <[email protected]> > Gesendet: Freitag, 7. Mai 2021 07:39 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] patch: improve RoadMerger: allow to merge roads > with reversed points > > Hi Felix, > > just noticed that patch v3 still only looked for mkgmap:has-direction=1 in > one place. > > Anyway, I am very unsure how to handle the direction flag. It's probably > not > a good idea to transfer the flag too ALL lines which are created from one > OSM way. > > I also found some cases where roads are not merged because the angle is too > sharp. This was discussed > here:http://www.mkgmap.org.uk/pipermail/mkgmap-dev/2013q3/018649.html > I think it was introduced to avoid bad routing at places like > https://www.osm.org/node/606366325 where we don't want to merge the two > link > roads. > I think the angle should be ignored if only two roads with the same > attributes meat. Like here: https://www.osm.org/node/1387136827 > > Gerd > > ________________________________________ > Von: mkgmap-dev <[email protected]> im Auftrag von > Felix Hartmann <[email protected]> > Gesendet: Donnerstag, 6. Mai 2021 17:55 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] patch: improve RoadMerger: allow to merge roads > with reversed points > > ah okay, no worries I can patch it myself. > > On Thu, 6 May 2021 at 23:46, Gerd Petermann > <[email protected]<mailto:[email protected]>> > wrote: > Hi Felix, > > the patch possibly has an influence on routing, so I don't want to add it > to > the low-res-opt branch. > I can provide two binaries if needed. > > Gerd > > ________________________________________ > Von: mkgmap-dev > <[email protected]<mailto: > [email protected] > ap.org.uk>> im Auftrag von Felix Hartmann > <[email protected]<mailto:[email protected]>> > Gesendet: Donnerstag, 6. Mai 2021 17:42 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] patch: improve RoadMerger: allow to merge roads > with reversed points > > Could you directly push those patches to the low-res branch? I guess anyone > using it right now would like to try it with the patch.. > I will try it out tomorrow. > > On Thu, 6 May 2021 at 18:32, Gerd Petermann > <[email protected]<mailto:[email protected] > ><mai > lto:[email protected]<mailto:[email protected] > >> > > wrote: > Ahh, sorry, merge-roads-reversed-v2.patch was work-in-progress. v3 works as > described before. > > Gerd > > ________________________________________ > Von: mkgmap-dev > <[email protected]<mailto: > [email protected] > ap.org.uk><mailto:[email protected]<mailto: > mkgmap-dev-b > [email protected]>>> im Auftrag von Gerd Petermann > <[email protected]<mailto:[email protected] > ><mai > lto:[email protected]<mailto:[email protected] > >> > > > Gesendet: Donnerstag, 6. Mai 2021 12:30 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] patch: improve RoadMerger: allow to merge roads > with reversed points > > Hi all, > > here is the 2nd approach: > > RoadMerger can connect more roads if direction of the roads doesn't matter > reg. routing. Problem is that mkgmap doesn't know if direction matters > unless the oneway tag > says so. The patch > - implements new special tag mkgmap:has-direction=true which must be set > for > ways which shoud not be reversed. > I am not yet sure how to use this. My idea was that the style author knows > which types are direction depended and this should add > mkgmap:has-direction=true for those lines which should not be reversed. > Before road merging all map lines which were created for a given OSM way > are > checked. If any has a direction then all lines for the given OSM way are > marked to have a direction. > Maybe this needs more thinking. > > - The program checks if there is any line rule that uses > mkgmap:has-direction=true. If not, mkgmap will not reverse roads for better > merging. > - implement new experimental option --x-force-reverse-merge to override the > logic reg. mkgmap:has-direction=true. > > Reg. size the patch is probably not worth the effort. It just merges a few > more roads (I see maybe 3% more merges) and thus safes some KB in NET and > NOD. > I see this also as a preparation to do more merging in the low-res-opt > branch. > > Gerd > > ________________________________________ > Von: mkgmap-dev > <[email protected]<mailto: > [email protected] > ap.org.uk><mailto:[email protected]<mailto: > mkgmap-dev-b > [email protected]>>> im Auftrag von Gerd Petermann > <[email protected]<mailto:[email protected] > ><mai > lto:[email protected]<mailto:[email protected] > >> > > > Gesendet: Mittwoch, 5. Mai 2021 16:53 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] patch: improve RoadMerger: allow to merge roads > with reversed points > > Hi Felix, > > the patch contained two bugs: > - Roads with different direction are not merged when they are connected at > the beginning. > - angle calculation was wrong, maybe that rejected possible merges or did > the worse ones. > > When I talk about overlays I mean those lines which are created with the > continue statement or with overlays rules. > > Gerd > > ________________________________________ > Von: mkgmap-dev > <[email protected]<mailto: > [email protected] > ap.org.uk><mailto:[email protected]<mailto: > mkgmap-dev-b > [email protected]>>> im Auftrag von Felix Hartmann > <[email protected]<mailto:[email protected]><mailto: > extremecarve > [email protected]<mailto:[email protected]>>> > Gesendet: Mittwoch, 5. Mai 2021 16:46 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] patch: improve RoadMerger: allow to merge roads > with reversed points > > If the direction of a line is changed, will all lines created via continue > also be changed? If yes then this decreases the lines a lot where I would > need the special tag. If not it will get complicated... > Well and the patch itself so far only saved about 0.3% of total map size. > Better than nothing for no visual impact of course. > > On Wed, 5 May 2021 at 22:43, Gerd Petermann > <[email protected]<mailto:[email protected] > ><mai > lto:[email protected]<mailto:[email protected] > >> > <mailto:[email protected]<mailto: > [email protected] > om><mailto:[email protected]<mailto: > gpetermann_muenchen@hotmai > l.com>>>> wrote: > Hi Felix, > > no idea why you talk about waterways here. The thread is about a patch for > RoadMerger. As the name suggest this code merges roads, nothing else. > RoadMerger considers far more attributes of lines compared to the simple > LineMerger, not just the type and name but also all the attributes which > affect routing. > It will not merge oneways with opposite direction, nor does it merge roads > which are used in restrictions. > > My current approach is to implement the new special > mkgmap:has-direction=true > If the style sets this for a road or any of its overlay lines RoadMerger > should not reverse the road. > > Gerd > ________________________________________ > Von: mkgmap-dev > <[email protected]<mailto: > [email protected] > ap.org.uk><mailto:[email protected]<mailto: > mkgmap-dev-b > [email protected]>><mailto:[email protected] > <m > ailto:[email protected]><mailto: > mkgmap-dev-bounces@list > s.mkgmap.org.uk<mailto:[email protected]>>>> im > Auftrag > von Felix Hartmann > <[email protected]<mailto:[email protected]><mailto: > extremecarve > [email protected]<mailto:[email protected]>><mailto: > [email protected]< > mailto:[email protected]><mailto:[email protected]<mailto: > extrem > [email protected]>>>> > Gesendet: Mittwoch, 5. Mai 2021 13:04 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] patch: improve RoadMerger: allow to merge roads > with reversed points > > Actually when I think about it - reversing the direction for waterways > should be done anyhow - there is no waterway that flows in opposite > direction. Cliff lines most likely the same. > And for lines that are off center - that doesn't matter as long as all > resulting lines are reversed. It would actually be better as otherwise at > one point the right side jumps to the left and this could be prevented. > > Yes oneway roads (plus all copies created from it via continue) - those you > cannot merge. > > On Wed, 5 May 2021 at 18:47, Felix Hartmann > <[email protected]<mailto:[email protected]><mailto: > extremecarve > [email protected]<mailto:[email protected]>><mailto: > [email protected]< > mailto:[email protected]><mailto:[email protected]<mailto: > extrem > [email protected]>>><mailto:[email protected]<mailto: > extremecarver@gma > il.com><mailto:[email protected]<mailto:[email protected] > >><mail > to:[email protected]<mailto:[email protected]><mailto: > extremecar > [email protected]<mailto:[email protected]>>>>> wrote: > will that patch also work on the low resolution branch, or only against > trunk? > > On Wed, 5 May 2021 at 18:05, Gerd Petermann > <[email protected]<mailto:[email protected] > ><mai > lto:[email protected]<mailto:[email protected] > >> > <mailto:[email protected]<mailto: > [email protected] > om><mailto:[email protected]<mailto: > GPetermann_muenchen@hotmai > l.com>>><mailto:[email protected]<mailto: > GPetermann_muenchen@h > otmail.com><mailto:[email protected]<mailto: > GPetermann_muenche > [email protected]>><mailto:[email protected]<mailto: > GPetermann_mue > [email protected]><mailto:[email protected]<mailto: > GPetermann_ > [email protected]>>>>> wrote: > Hi all, > > up to now RoadMerger doesn't merge (combine) two roads if the have > different > directions. This is OK for oneway roads but I see no need for this with > other roads. The attached patch changes this. It has an influence on file > size (safes a few KB in each tile) and very likely also on routing, > hopefully to the better/faster. > It also reduces zig-zagging in the low-res-opt branch. > > Strangely enough almost all was already implemented, so maybe WanMil (the > original author) tried that before and found a reason not to do it. Will > search the archives later... > > Gerd > _______________________________________________ > mkgmap-dev mailing list > [email protected]<mailto:[email protected] > ><mailto > :[email protected]<mailto:[email protected] > >><mail > to:[email protected]<mailto:[email protected] > ><mai > lto:[email protected]<mailto:[email protected] > >>>< > mailto:[email protected]<mailto: > [email protected]> > <mailto:[email protected]<mailto: > [email protected] > >><mailto:[email protected]<mailto: > [email protected]. > uk><mailto:[email protected]<mailto: > [email protected] > .uk>>>> > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > -- > Felix Hartman - Openmtbmap.org & VeloMap.org > > > > -- > Felix Hartman - Openmtbmap.org & VeloMap.org > > _______________________________________________ > mkgmap-dev mailing list > [email protected]<mailto:[email protected] > ><mailto > :[email protected]<mailto:[email protected] > >><mail > to:[email protected]<mailto:[email protected] > ><mai > lto:[email protected]<mailto:[email protected] > >>> > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > -- > Felix Hartman - Openmtbmap.org & VeloMap.org > > _______________________________________________ > mkgmap-dev mailing list > [email protected]<mailto:[email protected] > ><mailto > :[email protected]<mailto:[email protected]>> > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > _______________________________________________ > mkgmap-dev mailing list > [email protected]<mailto:[email protected] > ><mailto > :[email protected]<mailto:[email protected]>> > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > -- > Felix Hartman - Openmtbmap.org & VeloMap.org > > _______________________________________________ > mkgmap-dev mailing list > [email protected]<mailto:[email protected]> > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > -- > Felix Hartman - Openmtbmap.org & VeloMap.org > > _______________________________________________ > mkgmap-dev mailing list > [email protected] > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > _______________________________________________ > mkgmap-dev mailing list > [email protected] > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > -- Felix Hartman - Openmtbmap.org & VeloMap.org
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