[Tagging] Opinion on meaning of tracktype, smoothness and surface for routing
dbannon at internode.on.net
Thu Mar 20 22:18:18 UTC 2014
On Thu, 2014-03-20 at 15:02 +0100, André Pirard wrote:
>Following a gentle dispute on OSM-talk-be about the class of a
>particular road, I pointed out without any follow-up that road
>classification (primary ... tertiary, as well as national ... local on
>IGN maps) is very subjective but that the road width is very
>objective. Moreover, the width can be very easily measured with JOSM >
Andre, I guess we can measure the width of a road to a reasonable
accuracy via sat images. But I am not sure what that tells us. We cannot
assume a relationship between width and quality of the road can we ? Not
here in Australia anyway, many of the outback roads that are typical of
the subject of this discussion are quite wide, wider than some of our
fancy freeways closer to population centers.
If we wanted to measure vibration I guess we could have a process to
calibrate individual car's suspension. Maybe something like driving over
a set of steel pipes of defined size a defined distance apart ?
However, I doubt if we'd achieve anything useful, the sort of roads we
are talking about are usually quite erratic, smooth sections then
substantial holes or what ever. You slow down for the holes or you break
something ! But interesting idea....
> Of course, the closely related parameter is speed.
> Two other optimizing data for routing appear to be readily available:
> declivity as contour lines and straightness which is computable from
> the map of the road.
> I think that the only left parameter (beside varying weather, of
> course) is what you deal with: surface.
> Not only "will the car be hopping?" but also "is it slippery?", the
> latter only as a local condition.
> If we could find an indisputable value for road surface, we could
> build a very valuable routing database, probably innovative but
> unfortunately easy to steal.
> But could we find an objective measure of the surface? That is, such
> that everyone comes the the same value, not subjective.
> While reading your texts, I've had a crazy idea: measuring vibration
> in the car. There are Android vibration measuring programs like
> Vibration Monitoring. Alas, car vibration is very much dependent on
> car suspension. But would some of us experiment this or another idea
> and come up with a solution?
> Wouldn't it be great to organize a well thought out worldwide road
> quality tagging party?
> Sadly, traffic restriction tagging is in a miserable state. People
> even laugh at me, and that is at themselves, when I talk of GPS. More
> of this later, I hope.
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