[OSM-talk] Edit war on the wiki "map features"

[sylvain letuffe]

First  comment on the "ChrisFC" problem
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> to be that there's a lack of values
Is that what you understood he meant ? 
I am a bit lost in trying to understand what he does propose to make things 
better or to give new values...

I thought it was about not good words or too subjective values, or that we 
didn't manage to understand his very interesting point of vew that I could 
resume by :
"When you have objective criteria and a less stupid value set. Not before. 
Chriscf 11:30, 4 November 2008 (UTC)"

Even if it was mentionned many times that it was in no way "perfectly 
objective" values because it is impossible

Second comment I have read previously is :
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"Instead of tagging "usable_for_trucks=no" do something like "max_height=2.5 
meters" and "max_weight=10 tons". This way it is more useful"

Yeah, perfect idea, but impossible in our case : we have tried hard to 
perfectly describe a track, but that would require so many informations that 
no one will ever tag it.
* max slope in %, max turn in °
* max size of stones/gravel, mean size of stones/gravel
* presence of tree branch, lieves
* mud, sand, water, roots
* depth of max holes, mean size holes
* min distance between two holes

I'm trying to imagine myself with a ruler ! And think of the poor guy 
configuring his GPS :
- wheel size, max possible slope, crampons size, power engine, min distance 
between flat road and motor engine, tires pressure !

That previous example is not aware of some places's reality. max_height=2.5 
meters is easy to tag when there is a sign saying it. But not every tunnels 
or way in that world have a sign giving the width or the heigh, and even 
more, saying size of roots in cm on the way. It then boils down to two 
choices :
a) don't tag those things and stay un-informed
b) make a rather good guess until someone destroys his truck's roof and come 
and correct the data with X cm less than the actual Y meters

The surface tag is a bit of that kind and has not been able to answer the 
question "is it usable"

third comment :
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"and tracks which might or might not be accessible (and
then I'd do things like bicycle=yes, car=no or whatever if there was
any doubt)"

Are you so sure it's just that binary ? It is not until you have mentionned 
what vehicle you are using, and that's what smoothness is done for.

for "car=no" this is one of the main concern of this proposal : It tags 
physical properties.
How will you then make the difference between the already existing "car=no" 
that mean "you are not allowed" to go there with "you are not physically" 
able to go there ?
Perhaps you don't care, perhaps I do care. Some times in life, a law has said 
something, but you might still want to overcome that law, and since a map is 
tagging reality of things, I would then tag a forbidden passable track with :
highway=track
motorcar=no
smoothness=bad

sounds stupid ? I'm sure you all can guess at least one usage for that, even 
if it is almost bad faith

I've heard that tracks are all motocar=no in germany, but still, I strongly 
suspect people in germany to take their responsability, pay the bill if they 
are cought, be still want to know if it is passable

And the last one I want to comment :
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I don't see how you can use smoothness to say
smoothness="ok for a Renault Trafic but I wouldn't try it in a Clio.
A Ford Mondeo would probably make it if it has a manual gearbox, but
the automatics might struggle on the slippier bits"

Easy answer : you can't. 
And no tag will ever cover that. Does that mean we have to let it go ? No 
because it make a rather "good guess" of what can or cannot drive on it.

Ski slopes have 4 levels of difficulty, does that say you will or won't have 
problem skiing on ? no it doesn't : you have yourself the need to make 
a "good guess" of what you level is.

All those mapping tags, wich ever they are, don't prevent anyone from using 
their brains

Even the previous sign saying 2.5 meters will not make me drive at 130 km/h 
with my 2.4999 meters truck under it

PS: so, don't you think wiki would be good to talk about all that ? (or a 
forum ?)

--
sly
sylvain letuffe