> Date: Sun, 29 Sep 2013 13:01:17 +0200
> From: wmgcnfg@web.de
> To: mkgmap-dev@lists.mkgmap.org.uk
> Subject: Re: [mkgmap-dev] highway count not fixed yet... - merge-roads-branch
>
> > WanMil wrote
> >> Hi Gerd,
> >>
> >> in my opinion recalculating the highway counter after removing the short
> >> arcs should fix all problems, shouldn't it?
> >
> > Don't think so. All routines that replace or add points after that must
> > make sure that they maintain the correct highway count.
> >
>
> Ok, which routines perform such modifications? I couldn't find any such
> modifications of MapRoad instances after the StyledConverter.
>
> >
> >
> > WanMil wrote
> >> I've added three changes to the patch:
> >> 1. When calculating the highway count ways with duplicate id are not
> >> considered. This avoid that all points of a duplicated way are preserved
> >> by all filters.
> >> I think this should be modified a bit. For the first and last point of
> >> those ways the highway count should be increased and also all points
> >> where another way is connected. I have no use case where this matters
> >> but I think it is the "correct" counting?
> >
> > No, it just increases the possibility that the counter overflows.
>
> Maybe that's true for the trunk but in the branch there are real cases
> where it matters.
>
> Assume the following two ways:
>
> x>>>>>>>>>x===========x
> 1 2 1
>
> (x = Node; >> oneway line; === oneway=no; highway count below nodes)
>
> The style might duplicate the oneway=no way into to oneway=yes ways
>
> >>>>>>>>>>>
> x>>>>>>>>>x<<<<<<<<<<<x
> 1 2 1
>
> The merger might merge two of the ways:
>
> <<<<<<<<<<<
> x>>>>>>>>>x>>>>>>>>>>>x
> 1 1 1
>
> As a result the highway count of the 2nd and 3rd node is wrong. It
> should be 2 instead of 1. And AFAIK this difference matters.
>
>
> > Maybe we should not use this counter at all. The information that
> > it "hides" is that a point connects two or more roads.
> > I think a better solution would be to have a method markRoutingNodes()
> > which uses the counter and sets a bit flag in the coord instance.
> > This routine would replace setHighwayCounts() and resetHighwayCounts().
>
> I don't understand the advantage? I think maintaining the highway count
> is the same like markRoutingNodes(). How do you want to know when to
> call markRoutingNodes()?
>
> >
> >
> > WanMil wrote
> >> 2. I have added the problematic point in the error message of the
> >> MapBuilder in case a node is not a CoordNode. Just having the way id
> >> might not be enough information and the way also might have been merged.
> >>
> >> 3. I have moved the recalculation of the highway counters after the
> >> merge procedure. This should not change anything but it avoids a problem
> >> with merging...
> >
> > This is a good idea. Maybe do it before and after? That also means that
> > decHighwayCount() is obsolete, doesn't it?
>
> decHighwayCount() is obsolete as long as the highway counters are
> recalculated after mergeRoads(). When recalculating the highway count
> after mergeRoads() the RoadMerger does not care about (correct) highway
> counts (maybe a perf improvement might require correct highway counts
> but I don't know if the improvement is neccessary).
>
> >
> > Gerd
> >
> >
> >
>
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