The Dutch system of "polders" uses waterways for drainage, transport and irrigation, but not in a source2target way. Basically, a "polder" is a bathtub wherein several waterlevels (rings) are maintained through a network/maze of canals and ditches. When it rains a lot, water is pumped out of the polders; in dry periods, water is moved into the polders. All the waterways can drain, transport water/people/goods, and irrigate, as needed.
I guess we would have mainly waterway=canal and waterway=ditch, and very few waterway=drain where e.g. an industrial facility drains its wastewater. usage=* does not have meaning for most of these waterways. Flow direction vary. You do want to know if it's accessible/allowed for rowboats/motorboats/canoes. And maybe if you can cross them with a jumping-pole. Very important in some areas. Fr gr Peter Elderson Op di 4 jun. 2019 om 12:09 schreef François Lacombe < fl.infosrese...@gmail.com>: > Hi Joseph, > > Le mar. 4 juin 2019 à 01:55, Joseph Eisenberg <joseph.eisenb...@gmail.com> > a écrit : > >> However, the key "usage=" is also used with railways, eg usage=main, >> usage=branch. This might be considered a problem by some mappers, >> though at least all of the values used for railways are completely >> different than the list of values used for waterways and pipelines. >> > > To me it's not an issue but someone can indeed have different opinion. > > >> The other issue is that canals or ditches used for both irrigation and >> drainage (depending on the season) would need to be tagged like >> "usage=irrigation;drainage", and a long-distance canal that transmits >> irrigation water might need to be tagged >> "usage=transmission;irrigation" >> > > According to semantics of canals and ditches, a canal can't be used for > drainage and a ditch/drain shouldn't be used for irrigation > > Transmission should overcome any other value as it consists in leading > water from source to consumption places for more precise purpose. > We do have same approach with power lines or highway > You won't tag an actual motorway highway=motorway;service;residential for > the reason it leads to residential or service highways at its end. > > 2) Irrigation=yes >> >> With this tag, it would be possible to also use "drainage=yes", so a >> canal used for both drainage and irrigation could be "waterway=canal" >> + "irrigation=yes" + "drainage=yes" - this leads to using an extra >> tag, but doesn't require any semicolon-separated values. >> > > This shouldn't occur according to my comment upside. > usage values should not intersect with each others, I think there is no > need of yes/no values for it. > > Feel free to give any example where it doesn't work. > > All the best > > François > > _______________________________________________ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging >
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