I believe smoothness=* is very important in dry areas, including most of the western USA in summertime (when most people visit remote areas on track roads).
But a road that is very smooth, dry clay in summer, for example an unimproved track across a dry lakebed, will become impassible mud after a hard rainstorm if the surface is unimproved clay or silt. Here in Indonesia, I prefer to ride my 20 inch wheel bicycle across very bumpy track roads filled with with rough river stones rather than the smooth dirt on the side, after it rains, because the dirt become slippery mud, but the rocks stay just bumpy (and slightly slippery). So fully defining the condition of an unpaved road requires use of surface=*, tracktype=* and smoothness=* - unfortunately the later two can be hard to define clearly. Tracktype is a little easier to verify, if you take "solid" to mean "stones, rocks, pebbles and gravel" and "soft" to mean "sand, silt, clay and organic matter", you can estimate whether the majority of the roadway is made of one or the other. Certainly tracktype=grade2 (mainly gravel and stones) is quite obviously different than grade4 and grade 5 (mainly or totally unimproved soil), though the exact cut-off between grades may be hard to define. This means that some tracktype=grade5 are very nice, smooth surfaces in dry weather (that dry lake or salt playa for example), and only impassible after rain, but that's still quite important information, even in Arizona or Nevada. Joseph On 7/3/19, brad <bradha...@fastmail.com> wrote: > A pretty standard nomenclature on maps in the US for unpaved roads is > Improved Road > Unsurfaced Road (High Clearance) > Four Wheel Drive > Other variations exist , but not too dissimilar. > Pretty simple and anyone who spends time in the mountains or forest gets > a feel for what it means and has an idea what to expect. OSM is a mess > in this regards. The inconsistency make it difficult if not impossible > to render a good map. > > As I read the OSM wiki, smoothness=* is the relevant tag to distinguish > between a 2wd road, a high clearance road, and a 4 wheel drive road. > Surface is important too, but isn't sufficient if it's dirt/unpaved/ground. > > Unfortunately, the wiki for highway, in the section for track says: " To > describe the quality of a track, see tracktype > <https://wiki.openstreetmap.org/wiki/Key:tracktype>=*. " > But, as described in the wiki, tracktype is not very relevant to the > western US, since the first sentence of the description is > Solid/Mostly*/Soft. Perhaps relevant to the English countryside, but > the roads around here are usually Solid, but could be > smoothness:very_horrible. It seems redundant with surface=* also. > It looks like the common usage is to just use tracktype intuitively > (grade5 is 4wd even if it's Solid), and ignore the wiki & the smoothness > tag. Unfortunately its usage is inconsistent. I see roads that are > clearly (by onsite inspection) 4wd, tagged as grade2 and some graded > gravel roads tagged as grade2. > Tracktype could be sufficient if clarified, and if we were starting from > scratch that's what I would prefer. > > As I see it, two paths forward to improve this situation. > 1) Change the wiki for highway so it mentions Smoothness=*, and > de-emphasize tracktype=* > 2) Take the leading sentence mentioning Solid/Soft out of the tracktype > description (or de-emphasize it), and add more verbage about high > clearance or 4 wheel drive. There is some discussion on the > key:tracktype discussion page about adding grade6+. > 3) Ignore the wiki, and just use tracktype. I see in the discussion > page that is what many are doing. > > Thoughts? > > > > > > _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
