On Thu, 17 Dec 2020 at 12:43, Joseph Eisenberg <joseph.eisenb...@gmail.com> wrote:
> That example certainly looks like a landuse=basin or water=basin feature > with basin=retention > Maybe? But there's an awful lot of them tagged as reservoirs! Thanks Graeme > > On Wed, Dec 16, 2020 at 6:23 PM Graeme Fitzpatrick <graemefi...@gmail.com> > wrote: > >> In an Australian context, the most common are known as Turkey's Nest >> dams, because they're mounded up above the ground eg >> >> https://c8.alamy.com/comp/A6T7R0/turkey-nest-dam-on-outback-cattle-station-queensland-australia-A6T7R0.jpg >> >> For a full explanation: >> https://www.agric.wa.gov.au/water-management/excavated-tanks-farm-dams >> >> Thanks >> >> Graeme >> >> >> On Thu, 17 Dec 2020 at 11:53, Joseph Guillaume <josephguilla...@gmail.com> >> wrote: >> >>> That Wikipedia page is right. >>> The artificial grading mostly involves creating an (earthen) dam wall >>> (which is often also mapped), and the purpose is generally retention of >>> water rather than infiltration or detention, which is why the distinction >>> between reservoir and basin isn't clear cut to me. >>> >>> I'm having trouble thinking of it as a basin, but it does seem like this >>> is the intended tag. Thanks! >>> >>> >>> >>> On Thu, 17 Dec 2020, 12:29 pm Joseph Eisenberg, < >>> joseph.eisenb...@gmail.com> wrote: >>> >>>> What is a farm dam in this context? We don't have that term in American >>>> English. >>>> >>>> Is this perhaps an example of landuse=basin (or if you prefer >>>> water=basin) with basin=detention or basin=infiltration? >>>> >>>> https://wiki.openstreetmap.org/wiki/Tag:landuse%3Dbasin >>>> >>>> https://en.wikipedia.org/wiki/Dam_(agricultural_reservoir) >>>> >>>> -- Joseph Eisenberg >>>> >>>> On Wed, Dec 16, 2020 at 1:29 PM Joseph Guillaume < >>>> josephguilla...@gmail.com> wrote: >>>> >>>>> This discussion has convinced me not to use landuse=reservoir. >>>>> >>>>> It sounds like the only benefit is its historical use, whereas I've >>>>> personally seen benefits of the natural=water approach. >>>>> >>>>> I've mapped quite a number of farm dams as natural=water without being >>>>> sure what subtag to use. >>>>> I now think that's because there isn't an appropriate subtag. I >>>>> definitely don't want to tag it as a pond. While a farm dam is >>>>> structurally >>>>> and functionally a reservoir, there are clear differences with large >>>>> reservoirs. >>>>> >>>>> Already now, farm dams tend to be mapped more prominently than I'd >>>>> expect. The dominant feature of these grazing landscapes is fencing, and >>>>> I'd therefore expect farm dams to appear on a similar scale to fences. >>>>> water=reservoir and landuse=reservoir wouldn't do that. >>>>> >>>>> One of the things I love about OSM is the ability to map >>>>> incrementally, which by definition results in incomplete, lower quality >>>>> maps that are constantly improving. If the priority was a high quality >>>>> map, >>>>> we'd map systematically (like Missing maps, but for everything that will >>>>> appear on a render) and not release an area until it was done. I wouldn't >>>>> be mapping. >>>>> >>>>> >>>>> On Thu, 17 Dec 2020, 1:26 am Tomas Straupis, <tomasstrau...@gmail.com> >>>>> wrote: >>>>> >>>>>> 2020-12-16, tr, 16:01 Mateusz Konieczny rašė: >>>>>> > >>>>>> https://wiki.openstreetmap.org/wiki/Tag:landuse%3Dreservoir#water.3Dreservoir >>>>>> > (just added) >>>>>> >>>>>> Thank you. Maybe it is better to discuss here before adding to wiki? >>>>>> My arguments on the points you've added: >>>>>> >>>>>> 1. Regarding benefit of having a combining level/tag natural=water. >>>>>> If today you would query all data with natural=water - you will get >>>>>> not only lakes and reservoirs grouped, but also riverbank polygons >>>>>> (totally different beast) and micro elements like water=pond. This >>>>>> could only be partly useful in the largest scale maps and only if you >>>>>> make very simple maps and for some reason use the same symbolisation >>>>>> for such different water classes. For example ponds usually have less >>>>>> complex and less prominent symbolisation because of their size and >>>>>> importance. Riverbanks would not need polygon labelling, but rather >>>>>> use river (central) line for label placement. Most of GIS/Cartography >>>>>> work goes in middle/small scales and it will be impossible to use only >>>>>> natural=water there, you would have to add "and water not in >>>>>> ('riverbank', 'pond', ...)". This erodes the benefit of "one tag" and >>>>>> makes it of the same complexity from coding perspective as original >>>>>> water scheme. >>>>>> >>>>>> 2. Very important disadvantage of water=reservoir from >>>>>> cartographic/gis perspective: it allows mappers to NOT differentiate >>>>>> between natural lakes and man made reservoirs. If first point >>>>>> describes how different classes are USED, this second point is about >>>>>> how these classes are CAPTURED. >>>>>> >>>>>> Did I miss anything? >>>>>> >>>>>> _______________________________________________ >>>>>> 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 >>> >> _______________________________________________ >> 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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