First comment on the "ChrisFC" problem -----------------------------------------------------
> 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 : -------------------------------------------------------- "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 : --------------------- "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 : ------------------------------------------------ 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 _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
