Just two outers is a regular use of multipolygon. If the tags of two areas are the same, you can represent two or more distinct areas as a multipolygon
If you have one area as a multipolygon with an inner, a separate closed way can be used as an extra outer, it will then get the attributes of the multipolygon. Major renderers support this. One parking lot on two sides of a road is perfect for this method. Best, Peter Elderson Op di 14 jul. 2020 om 16:55 schreef Lionel Giard <lionel.gi...@gmail.com>: > Wouldn't a multipolygon with just two outers solve that parking case? >> Best Peter Elderson >> > > That's a bit of a stretch of the multipolygon definition as there is no > inner ring. I never used multipolygon for anything else than complex > geometry (with inner ring(s)) and that seems to be what the feature is for. > > As we already have the site relation for grouping features that are part > of the same thing, but disjoint, i think that it is good to use it. It also > solves the problem when mappers use multipolygon for two polygons sharing > the same edge (it is forming an invalid geometry), while with site relation > it is not a problem. Another advantage is that it is quite easy to edit. > You just need to add or remove a feature : no specific roles (yet) or order > needed. > > Le lun. 13 juil. 2020 à 23:29, Volker Schmidt <vosc...@gmail.com> a > écrit : > >> >> >> On Mon, 13 Jul 2020 at 22:56, Martin Koppenhoefer <dieterdre...@gmail.com> >> wrote: >> >>> actually all of these could be „grouped“ with tags alone, e.g >>> distributed museums could have an identifying „network“ tag (or sth >>> similar). >>> >> But why invent a new network tag, if we have a site relation, waiting to >> be used. (I was thinking of open air museums, where the various exhibits >> are spread over the landscape) >> >>> For power plants a site might be appropriate, if an area does not do it >>> and you don’t want to rely on only tags. >>> >> If you have ever looked at the complexities of a hydro-power-plant with >> dams, lakes, pipes, turbines deep in the mountains or in dedicated >> buildings . they are really complex, and only parts of it are visible on >> the surface. >> >>> In theory objects like the Great Wall in China can and should be modeled >>> as areas, although they seem to be linear in nature, they are also thick >>> enough to „require“ an area representation in order to be well mapped in >>> the scale of OpenStreetMap (you can walk on it). >>> >> That's not true - you can walk on parts of it, other parts are completely >> missing, others are heaps of stones. >> >>> In practice we would also want a way to have preliminary mapping as a >>> line, and mixed geometry relations. A multipolygon relation for all parts >>> of the great wall would likely be broken every day, and would be over the >>> member limits for relations. >>> >> It's not a multipolygon - it is bits and pieces, some connected, same >> not. Some may be linear (in first approximation). >> >> >>> Would those that are in favour of using a site relation for a linear, >>> circular, interrupted structure, 19km long and some meters wide, also see >>> it as a good relation type for the Chinese Great Wall? >>> >> You lost me with your question here. >> >> Volker >> >> >> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> >> Virus-free. >> www.avast.com >> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> >> <#m_-2578868543391359494_m_8037950653339377666_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> >> _______________________________________________ >> 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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