Re: [Tagging] Feature proposal - RFC - Documenting feet as an an optional elevation unit
Minh Nguyen writes: >> It's a slippery slope, and pretty soon \pi is 3. > > Poor Indiana. ;-) The definition of the foot would apply to the ' and > ft abbreviations in every context, not just the ele=* key, so I'd > suggest considering it separately, probably without the formality of a > vote. The main unit symbol listing has come together more informally > over the years. [1] > > Sooner or later, OpenHistoricalMap will have a lot of fun with this issue... > > [1] https://wiki.openstreetmap.org/wiki/Map_features/Units A fair point that it's generic, and while that page does not say "international foot", the conversion given is the modern/interntional one. So I think we're all set. I would expect elevations in feet in NGVD29 to be in survey feet. It's not so much a special feet for surveying as the definition before the 50s, and too hard to change for horizontal control, while ignorable just about everywhere else. But, the difference is tiny, and elevations in NGVD29 are more or less by definition of poor accuracy anyway. I'm glad to see the usual suspects are still here! ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Feature proposal - RFC - Documenting feet as an an optional elevation unit
On 29/1/24 06:30, Philip Barnes wrote: The legal definition of a foot is of course 0.348 m. "Since an international agreement in 1959, the foot is defined as equal to exactly 0.3048 metres'. Phil (trigpoint) NPL has a nice history on length measurement http://resource.npl.co.uk/docs/educate_explore/posters/bg_historyoflength_poster.pdf Even in the USA the survey foot is depreciated. https://amerisurv.com/2023/02/09/the-deprecation-of-the-us-survey-foot/ Depreciation in the US may be 'complete', at least in government circles, in 2025... On 28 January 2024 18:57:45 GMT, Minh Nguyen wrote: Vào lúc 04:08 2024-01-28, Greg Troxel đã viết: Minh Nguyen writes: Vào lúc 19:50 2024-01-27, Brian M. Sperlongano đã viết: Uh so I did the math, and unless I've got this wrong, the difference between survey feet and international feet for tagging, let's say, Mount Everest, is less than seven one-hundredths of an inch. So I'm really not even sure why we're discussing it beyond the fact that we're all nerds about this sort of thing. You got me. :-) The actual proposal doesn't mention the foot's two definitions at all, and so far I'm planning to keep it that way. I think it's important to be definitionally correct, even if it doesn't really matter. It's a slippery slope, and pretty soon \pi is 3. Poor Indiana. ;-) The definition of the foot would apply to the ' and ft abbreviations in every context, not just the ele=* key, so I'd suggest considering it separately, probably without the formality of a vote. The main unit symbol listing has come together more informally over the years. [1] Sooner or later, OpenHistoricalMap will have a lot of fun with this issue... [1] https://wiki.openstreetmap.org/wiki/Map_features/Units ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Feature proposal - RFC - Documenting feet as an an optional elevation unit
On 1/29/24 02:12, Graeme Fitzpatrick wrote: https://japannews.yomiuri.co.jp/society/noto-peninsula-earthquake/20240111-161375/ See also: https://strokkur.raunvis.hi.is/gps/8h.html (Icelandic data, with maggma intrusions, tectonic movement, quakes and eruptions) -- Cheers, Jeremy ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
