[Tagging] Feature Proposal - RFC - trafficability

[Wolfgang Hinsch]

Am Samstag, den 04.01.2014, 11:19 +0100 schrieb BGNO BGNO:
> We don't have to stick to the term "trafficability". What would be a
> good alternative?
> 
> - usability
> - passable
> - passability (there is an abandoned proposal suggesting this term)
> - usable_if
> - ???
> 

None of them.

I think it's a bad idea to tag interpretations.

You look at a road and see whether it's passable or not. But what do you
see in reality? You cannot see any kind of usability, this is only an
interpretation of you.

You see obstacles? What obstacles? Water, sand, grave, rocks? What does
this mean to all road users?

You may have a well built motorway in a very good state. But for you
it's impassable. Why? Well, you are taxiing an A380. Or you are going by
bike or on foot.

You want to cross a river? No bridge? No problem, you are driving a
hovercraft. Or there is a bridge, but it is impassable because you are
driving a tank and the bridge would collapse.

Even if two people are going by the same class of vehicle, the way may
be passable only to one of them.

I know a mountain-biker who has fun if the way is a blind end in front
of a river with a depth of less than 1 m, followed by 200 m of mud and
500 m of scrub before reaching the next way.

Some people would describe the way up to Mount Everest or K2 as quite
passable.

These examples are extrem, of course. But when we were mapping for the
bicycle map of Lübeck, we discussed how to tag the "quality of way".
It's not possible, because you don't know which exact vehicle will pass
and what kind of driver or walker comes along.

You can create a map for a certain group of road users and interpret the
tags of the ways according to your target group. But you cannot tag it
in OSM because OSM has no special target group. OSM is for every class
of vehicle, driver or walker.

Please tag what is to be seen "on the ground". If the surface consists
of mud, tag surface=mud (or any appropriate tag). If it's flooded at
hight tide or monsoon season, tag flooded=high_tide,
flooded=monsoon_season or something better, but don't tag
hight_tide=impassable because I might be driving an amphibious vehicle
and want to be routed through.

Cheers, Wolfgang