Hi Manfred,
thanks for your proposal. I think there are a lot of reasons why the new
curviness() function might be a bad idea (it depends on how well a way
is mapped; its value is unreliable due to the mapping to the garmin
coordinates; etc.).
Anyhow I think it's worthy to play a little bit with it :-)
I will try to add a first implementation of this function so anybody can
test it. If it does not get enough supporters we can throw it away later on.
WanMil
> Hi all,
> moving away from fixed built-in, to a flexible, configurable mkgmap can
> give a great progress to the quality of maps.
> You do a great job, and I really appreciate your work
> Thinking about maxspeed:practical, which can be used to initialize
> maxspeed in some cases, I thought about rural areas, which do not have
> any maxspeed, or maxspeed:practical information included in OSM data:
> The new curviness() function (useful for ways).
> Such a function could e.g. return the sum of direction change at every
> point, divided by the way's length.
> This could give an estimation for the maximum practical speed.
> /--------------------------------------------------------
> | ...
> | maxspeed!=* & maxspeed:practical!=* & curviness()<0.3 {set
> maxspeed:practical=120}
> | maxspeed!=* & maxspeed:practical!=* & curviness()<0.5 {set
> maxspeed:practical=100}
> | maxspeed!=* & maxspeed:practical!=* & curviness()<0.8 {set
> maxspeed:practical=80}
> | ...
> | maxspeed:practical=* {set maxspeed=${maxspeed:practical} }
> | ...
> \------------------------------------------------------------
> However, the values are only fictional values, and does not include a
> physical background. But anyway, it might help improve routing quality,
> especially in poor mapped areas
> It also could help to improve maps for motorbikers, who tend to prefer
> curvy roads.
> Could you imagine that such a function would make sense?
> Cheers
> Manfred
> *Gesendet:* Freitag, 30. August 2013 um 22:19 Uhr
> *Von:* WanMil <[email protected]>
> *An:* "Development list for mkgmap" <[email protected]>
> *Betreff:* Re: [mkgmap-dev] [PATCH v2] Move maxspeed calculations to
> style file
> > Felix> only downwards, is what everyone expects, but not what mkgmap did
> > Felix> so far. I critisized this quite often in the past....
> >
> > Thanks Felix - that's what I wanted to know. I obviously overlooked
> > your previous complaints!
> >
> > The style rules you present do look quite unwieldy - perhaps it's
> > possible to simplify by setting initial defaults, and using those to
> > allow revising downwards:
> >
> > /--------
> > | highway=motorway { add mkgmap:road-speed-class = 7 }
> > | highway=trunk { add mkgmap:road-speed-class = 6 }
> > | ...
> > |
> > | maxspeed:practical=* { set maxspeed=${maxspeed:practical} }
> > |
> > | maxspeed=* & mkgmap:road-speed-class > 1 & maxspeedkmh() <= 5
> > | { set mkgmap:road-speed-class = 1 }
> > | maxspeed=* & mkgmap:road-speed-class > 2 & maxspeedkmh() <= 20
> > | { set mkgmap:road-speed-class = 2 }
> > | ...
> > \--------
> >
> > Is there any reason why that wouldn't work?
>
> Should work.
> As I answered Felix I will come back later on to improve the default
> maxspeed rules.
>
> WanMil
>
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