OK, this discussion is huge and conducted in a great manner. But being so huge, I feel lost ! So, here is an attempt to summarize where we are and what the options seems to be. Maybe by identifying what we already agree on, we can see the way into the rest ?
If people think its a good idea I could post a more evolved summary onto my OSM wiki page where we could all have a hack at it, might be more manageable than the mailing list ? If nothing else, we need to break this very complicated problem into manageable hunks. Think of this somewhat like a flow chart, I just have not drawn it up... Do we all agree that its important that significant maps, such as the one on the OSM website, shows some indication if the road may be in a state where some drivers are uncomfortable (right through to dangerous) ? If Yes, proceed, if No, please explain why not. You may like to address this - http://www.abc.net.au/news/2012-11-07/25yo-man-dies-of-thirst-in-outback-queensland/4357380 There are lots more. Tourists from outside Australia are at particular risk. OK, assuming we agree we want 'something' ... We need some tag (or tags) associated with a way that tells a rendering engine this way is one that might need caution. We can try and use existing tags or invent a new one. The "new one" option (such as BGNO's trafficability) could be tuned, based on experience, to do exactly what we want. On the other hand there are currently no ways in the database using that new tag. There are 3 million surface= and 2.5 million tracktype= tags in there. Mappers put used those tags in there for a reason. If you want a new tag defined, please say so, maybe with a new subject ? Continuing on, assuming we support using existing tags, which ones ? At lease three 'approved' candidates, four if you include 4wd_only. Surface= has about 3 million ways that are what we, in Oz, call 'unsealed', dirt, sand, gravel, unpaved and so on. This is not a bad fit but neither is it perfect. http://wiki.openstreetmap.org/wiki/Surface "To provide additional information about the physical surface of roads/footpaths...." However, my experience is that a precise statement about the surface does not necessarily relate to its "trafficability" (thanks for the term BGNO!). I have driven sandy roads that were so easy and somewhere else, spent a day with a shovel digging through sand. Similarly, hard packed clay can sometimes be preferable to a made gravel road that has developed severe corrugations. And a sealed, tarmac road that is breaking up is a nightmare. Tracktype= has about 2.5 million grade2 and beyond ways. "Tracktype is a measure of how well-maintained a track or other minor road is." http://wiki.openstreetmap.org/wiki/Tracktype Thats a lot closer to what someone (or a router) might be wanting to know. It can and should be applied to all sorts of highway= ways, not just =track and that seems to be a major problem. In some people's view (Malenki..), it should be used only when highway=track. I and several other people (and the wiki) disagree. The values of Tracktype are not intuitive. The values are linearly expandable, to cover more extreme road conditions, grade6 is already widely used but not approved. Smoothness= has about 25 thousand ways. Thats drawing the line at very_bad. But there are another 40 thousand 'bads' so its hard to call. http://wiki.openstreetmap.org/wiki/Key:smoothness I am personally convinced this tag would be used heaps more if the values did not seem to make some moral judgment ! As I said before, I could never label the pretty road I live on as "horrible". There is some support for making a new set of values and that would be cool (Fernando, Martin). But has the horse already bolted ? Surface= and tracktype each have more than 100 times more use. Further, if we come up with new values, why not a new name ? Truth is, 'smoothness' is only a small aspect of trafficability (there, I used it again!). 4wd_only=yes. Used 3 thousand times, more in Australia than elsewhere. In hindsight, maybe it could have done with at least three values, 'recommended', 'yes', 'extreme'. It does cut in somewhat beyond the spot we are talking about, I get the impression that people want a road labeled differently long before we get to 4wd_only=recommended. Any one of the above, or a combination ? Personally, I think a combination would be over complicating it. Just my view. Other Issues - How to render it ? That can come later on I guess. Wolfgang, Peter, Janko, Gerald warns about subjective tags. Truth is, almost everything we record is subjective to some degree. I'd take the legal approach where they talk about a "reason person's view". For a normal road, thats someone driving a conventional car. For a mountain bike track, its someone riding a mountain bike.... Fernando pointed out that to make a truly objective assessment, we'd need many more tags and some elaborate technology to measure. Gerald suggested a smartphone app to do the measuring but is he allowing for variation of suspension in the vehicle in use ? David S and Dominic don't seem to want more detailed measures either. David S reminds us what highway= tag is about. Its to describe the purpose of a road, not in any way its "trafficability" (David S said "usability but I am starting to like trafficability...). he is right but the anomaly is highway=track, its use opens up, at present, the tracktype modifiers, wrong, wrong.... One important effect of the highway= tag is "more important" roads get rendered at lower zoom numbers. Useful when you want to see how to get from A to B. Sadly, we hear of people taging important roads as =track so their usability can be described by tracktype. And then you cannot see them at all at sensible zoom levels. Sigh.... Now, I have not mentioned everyone nor every view, impossible ! Thats why I think its time to move to the wiki, perhaps show a series of options and just see who really wants to vote for what. But, I really must thank Fernando for driving this issue, its very, very important and damn hard as well ! David On Fri, 2014-01-03 at 21:10 -0200, Fernando Trebien wrote: > a massive contribution... _______________________________________________ Tagging mailing list [email protected] https://lists.openstreetmap.org/listinfo/tagging
