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[mkgmap-dev] Fw: Re: Curvy routing support: new function?

From Felix Hartmann extremecarver at gmail.com on Thu Jul 3 19:32:44 BST 2014

You are missing a big big point here!

The higher you put the speed, the bigger the time penalties for sharp turns.
So the only thing reasonable to do is ramp up the road_class, and keep 
or back down the road-speed..

But best give it some tries yourself by creating a sample map where you 
increase speed for some curvy roads based on name filters. You will 
likely notice that the result is rather the opposite. Especially if 
there are crossings...

On 03.07.2014 19:49, Manfred Brenneisen wrote:
> Hi all,
>> Gesendet: Mittwoch, 02. Juli 2014 um 08:46 Uhr
>> Von: "Felix Hartmann" <extremecarver at gmail.com>
>> An: mkgmap-dev at lists.mkgmap.org.uk
>> Betreff: Re: [mkgmap-dev] Curvy routing support: new function?
>> Well I have thought about this too - also new Basecamp has a curvy roads
>> preference - but what should mkgmap do about it?
>> You can calculate if a road is curvy or not, but what then? The only
>> thing you can do until mkgmap knows NT format maps which I think has a
>> special "tag" for this, is to increase the road-class.
>> Increasing the road-speed would be against your intentions - as the
>> higher the road-speed - the more garmin algo will punish you for curvy
>> roads...
>> So until we know how Garmin maps tell Basecamp/the GPS Unit to exclude a
>> road from curvyness punishment - the only thing you can do is to
>> increase the road-class...
>> I'm 100% sure the prefer curvy roads switch, works like avoidance -
>> looking for the curvy road indicator inside the map. There is absolutely
>> no change in routing in Basecamp if I set it or not with non NT maps...
> I devised myself a day to think about it. To be not too enthusiastic or conservative, as the future will be NT maps as you state correctly. Finally, I think:
> mkgmap could translate the physical shape of a road into different categories, e.g. by setting mkgmap:road-speed parameters. This is more analog than digital "curvy" or "not curvy" setting by just setting single bits (which are not widespread yet, NT only).
> One might want to differentiate between this way: http://www.openstreetmap.org/way/186500650 and that way: http://www.openstreetmap.org/way/106597772
> Which one is faster? Would you like to add the (highly unwanted!) maxspeed:practical tag to OSM data?
> Car map designers might want to lower speeds for curvy roads, motorcycle map makers would go the other way (knowing that the calculated travel time is incorrect)
> Adding style rules like
> highway=primary & curviness() > 50 {add mkgmap:road-speed-max=5}
> would not influence the map, only curvy roads are affected.
> Nobody is forced to use the new function (knowing that it slows down map generation if used). But as it is not a really big thing you might give it a try. I'll test, and report when it works correctly (for me :-))
> Cheers
> Manfred
>> On 01.07.2014 22:02, Manfred Brenneisen wrote:
>>> Hi all,
>>> Garmin offers "curvy roads" preferences for their zümo 390 and 590 devices.
>> -- 
>> keep on biking and discovering new trails
>> Felix
>> openmtbmap.org & www.velomap.org
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