Short summary of what we have ended up with so far. --------- *Variant #1* Keep both "drain" and "ditch" tags but update their definitions to make a clear cut between the meanings:
drain - Small artificial free flow waterways usually lined with concrete or > similar used for carrying away superflous liquid like rain water or > industrial discharge without letting it soak into the ground. Consider > using waterway=ditch for unlined channels used to drain nearby wet land. > Consider using waterway=canal for large unlined land drainage channels. https://lists.openstreetmap.org/pipermail/tagging/2019-January/042543.html ditch - Small artificial free flow waterways used to directly distribute > water to dry land (for irrigation) or collect water from wet land (for > drainage). Irrigation ditches can be lined or unlined, drainage ditches are > usually unlined to let water soak through the land into them. Ditches may > have short lined segments at waterway turning points or intersections with > roads or paths to prevent erosion. Consider using waterway=canal for larger > channels *that convey water from or to ditches. Consider using > waterway=drain for usually lined superflous liquid drainage channels. https://lists.openstreetmap.org/pipermail/tagging/2019-January/042566.html *Variant #2* Combine "ditch" and "drain" tags into one. ditch - a narrow channel dug at the side of a road or field, to hold, bring or carry away water or industrial discharge. (a) The purspose can be clarified by usage=irrigation/drainage attribute. Drainage is assumed by default if not defined. (b) Industrial discharge ditches can be clarified by industrial_discharge=yes attribute. (c) Lined channels can be clarified by lined=yes+liner=<material> attribute. note: I'm not sure about the attribute names. --------- Personally I lean toward variant 2 because - if a drain is a digged out channel, then it is a ditch, and no need to clarify the purpose because drainage is assumed by default - if a drain is not a digged out channel, then some absolutely different tags should be used like man_made=* or pipe_line=* - if you want to specify industrial discharge drainage then you have to use an additional attribute anyway to distinguish it from storm water drains. - if we had a separate tag for "drains" then lined would be assumed by default, but you would have to define lined=no attribute for unlined drains then. This seems to be the only point which would make the life easier with two separate tags. Cheers, Eugene сб, 2 февр. 2019 г. в 19:44, Eugene Podshivalov <yauge...@gmail.com>: > Not all ditches can be called drains and not all drains can be called > ditches and there is some overlapping in their meanings which causes the > confusion. > > I see three ways to go: > 1. Define the basic meanings from dictionaries and let users decide on > which tag to use, similar to Peter Elderson's version from the preceding > post. > 2. Allow some deviation from dictionary definitions to make a clear cut > between the two. This is similar to how "stream" is currently restricted to > the maning of "you can jump over it". > 3. Introduce some abstract notions with clear definitions of each > sub-notion. Similar to highway=track + tracktype=grade1,grade2 etc. or > boundary=administrative + admin_level=2,3 etc. > > Cheers, > Eugene > > сб, 2 февр. 2019 г. в 18:48, Peter Elderson <pelder...@gmail.com>: > >> If there is a drain worth mapping, I will map it as a drain. >> >> If the drain has the form of a ditch and I can see its only function is >> to be a drain, I will map a drain. Size and lining may be indicators, not >> definers. >> >> If a ditch has unclear function or multiple functions, I will map a >> ditch. If I think it’s worth mapping. >> >> I will not systematically retag drains to ditches unless the national >> community decides to do so. Automated edits: no way. >> >> Mvg Peter Elderson >> >> > Op 2 feb. 2019 om 14:22 heeft Hufkratzer <hufkrat...@gmail.com> het >> volgende geschreven: >> > >> > If we were discussing a proposal I would agree, but replacing >> waterway=drain by waterway=ditch + usage=drainage or sth. like that is not >> such an easy task. We already have 800k drains. I assume it requires a >> proposal with volting to deprecate drain, adaption of the presets, perhaps >> a mass edit. Who will do all this? Is the advantage of using waterway=ditch >> + usage=drainage instead of waterway=drain so immense that it is worth the >> effort? >> > >> > Am 02.02.2019 13:58, schrieb nwastra: >> >> +1 >> >> >> >> N >> >> >> >>>> On 2 Feb 2019, at 10:39 pm, Markus <selfishseaho...@gmail.com> >> wrote: >> >>>> >> >>>> On Sat, 2 Feb 2019 at 11:21, Sergio Manzi <s...@smz.it> wrote: >> >>>> >> >>>> Thank-you for confirming that, Mark. >> >>>> >> >>>> Personally I think we, in OSM, should stop with this folly of >> overloading English words with meanings they do not have in any dictionary >> (be it AmE, BrE, CaE, or whatever). >> >>>> >> >>>> Both the "ditch" and "drain" words can be used to describe certain >> features in English. The difference is essentially an etymological one, >> with one related to the process of excavation (dig -> ditch) and the other >> to the function of carrying liquids away (dry -> drain). >> >>>> >> >>>> If we want to precisely map certain characteristics of a feature we >> should do it explicitly through a correct data model that takes into >> consideration the particular aspect we are trying to communicate. We want >> to communicate the information that a (small) waterway is lined with >> concrete? Just say that with an appropriate tag, like e.g. lined=*, or >> lining=*. We want to communicate the information that a (small) waterway is >> used to carry waste water away? Once again, let's say that with an >> appropriate tag, like e.g. usage=* (please ignore if the specific tags I >> put in the examples are not of your liking: not the point here, let's >> discuss that later...). >> >>>> >> >>>> Arbitrarily overloading words with meanings they do not have in the >> common language is just a perfect way to Babel, that is a reduction in >> information. >> >>> + 1 >> >>> >> >>> _______________________________________________ >> >>> Tagging mailing list >> >>> Tagging@openstreetmap.org >> >>> https://lists.openstreetmap.org/listinfo/tagging >> >> _______________________________________________ >> >> Tagging mailing list >> >> Tagging@openstreetmap.org >> >> https://lists.openstreetmap.org/listinfo/tagging >> > >> > >> > --- >> > Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft. >> > https://www.avast.com/antivirus >> > >> > >> > _______________________________________________ >> > Tagging mailing list >> > Tagging@openstreetmap.org >> > https://lists.openstreetmap.org/listinfo/tagging >> >> _______________________________________________ >> Tagging mailing list >> Tagging@openstreetmap.org >> https://lists.openstreetmap.org/listinfo/tagging >> >
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