[mkgmap-dev] [PATCH v1] modify road speed and class from a POI

Wed Oct 14 09:34:04 BST 2009

Hi Felix,

> Mark Burton wrote:
> > This is something that was briefly discussed not too long ago and the
> > idea is that a road's speed or class can be modified by the
> > presence of a POI that defines new values for either/both of them. This,
> > hopefully, will make ways that have stuff like traffic signals and
> > crossings, etc. less attractive to route over.
> >
> > The values are specified using mkgmap:road-speed and mkgmap:road-class
> > tags added to the POI.
> >
> > These tags expect an integer value, optionally preceded by a + or -
> > which make the adjustment relative to the original value.
> >
> > For example, mkgmap:road-speed=3 sets the speed to 3 and
> > mkgmap:road-speed=-1 reduces the speed by 1 from whatever value it had
> > before.
> >
> > Here's some possible rules for the points file:
> >
> > highway=traffic_signals { add mkgmap:road-speed = '-1' }
> > highway=crossing { add mkgmap:road-speed = '-1' }
> > highway=mini_roundabout { add mkgmap:road-speed = '1' }
> >   
> Wow that sounds really great!
> Will try it out tomorrow. Especially increasing it based on points 
> sounds great
> 
> is road-speed a typo? Should it be road_speed?

No, it's not a typo.

> Is it really the POI that introduces this change on the unit, or is 
> mkgmap changing it based on the compile process?

It's mkgmap, taking the info in the POI and applying it to a region of
the way around the POI.

> I would never have thought that Garmin takes POIs into account when 
> routing (will also have to see whether this works on all units in case 
> it is not mkgmap).

I believe the same as you that the GPS ignores POIs as far as routing
is concerned.

> This will really help to make city streets less attractive and pathes 
> and footways that are outdoor more attractive (fewer traffic_signals, 
> crossings, etc...).
> > The region of the way that has its speed/class modified is limited to
> > the closest points either side of the POI. Not sure if that's the right
> > thing to do yet. Needs playing with.
> >
> > You need to specify the --link-pois-to-ways option to enable this
> > functionality.
> >   
> The link-pois-to-ways adds no access restrictions if not specifically 
> given in the style-file, does it?

That option adds nothing itself, all of the info it works on has to be
added by the style file (or be in the original OSM data). So if a POI
has an access restriction, that could be transferred to the way (which
is what we want in the case of barrier POIs.

> Thanks for the last two mails, both really good things to get better 
> routing!

That's the motto of the month - improve routing!

Cheers,

Mark