Sure! I was just sidestepping about the parking lot example. Best, Peter Elderson
Op di 14 jul. 2020 om 18:34 schreef Volker Schmidt <vosc...@gmail.com>: > Sorry to keep riding this horse, but many of my examples have areas, ways > and nodes as members, so they cannot be described by any kind of polygon. > Lets take my favourite example of a dismantled railway. > It contains: > > - nodes: tourist information tables > - ways: embankments, all kinds of highways > - areas: former railway buildings, bridge structures, vegetation areas > (that correspond to the former rail bed) > > > > > On Tue, 14 Jul 2020 at 18:17, Peter Elderson <pelder...@gmail.com> wrote: > >> https://wiki.openstreetmap.org/wiki/Multipolygon_Examples example 1.7 >> describes disjunct outers. >> >> Too bad you have to wrestle through some very complicated examples to get >> there if you start at the beginning. And, these complex examples should not >> be followed, because they advocate tying landuse to ways, borders to ways >> and other stuff you really should not do if you want to keep the map >> unbroken. >> >> Best, Peter Elderson >> >> >> Op di 14 jul. 2020 om 18:05 schreef Peter Elderson <pelder...@gmail.com>: >> >>> 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_-4227485519747961164_m_-1194931303057811726_m_7578338272934009314_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 >>>> >>> _______________________________________________ >> 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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