Talk:Proposed features/ele:regional

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We already have tag for this and it's called "ele". Despite what wiki says, people are just copying heights from local maps in local reference system into this tag. Those who knows wgs84 values are using ele:wgs84. Maraf (talk) 11:05, 3 May 2020 (UTC)

The description for "ele" states that elevations are given in WGS84 (despite this only partially true). ele:regional explicitly states it is for regionally typical units (i.e. as commonly found on signs). I agree and encourage the use of more specific keys like ele:wgs84=*, but I do not expect Joe Mapper to be aware of the respective reference. Ele:regional makes it simple to state: I just read this value off some sign (or similar source) and do not want to bother with the details. --Dieterdreist (talk) 13:04, 3 May 2020 (UTC)

ele:local=*

What makes this better? I can't follow Talk:Key:ele:local#definition. Wouldn't *:local=* be easier to understand and more straightforward than *:regional=* for the "local" stated elevation. There are many other "local" keys such as loc_ref=* and loc_name=* -- Kovposch (talk) 15:25, 6 May 2020 (UTC)

The tag does not have any definition, but you can find something on the discussion page. Last time I read there I had come to the impression that the tag was for storing local heights related to a local reference point (relative heights). There isn't more information on the page. --Dieterdreist (talk) 15:35, 6 May 2020 (UTC)
Would eg ele:marked=* be more straight to the point then? To consider that, it may not always be known what's the reference datum, be it "local" or regional. -- Kovposch (talk) 09:28, 8 May 2020 (UTC)
I have in the past used ele:local=* for elevation collected from signs (on the grounds that ele=* is meant to be in WGS84, and signs tend to be relative to the national system), which is the same usage being proposed here. I was just about to propose sticking with ele:local=* when I heard of ele:local=* being used to indicate relative elevation (i.e. over a local reference point rather than sea level). A tag for “elevation in the reference system commonly used on the ground in that area” definitely makes sense, as I would consider that the dominant use case for elevation data entered into OSM (data from a GPS, which would be in WGS84, is too unreliable; mirroring a DEM into OSM is just a lot of maintenance effort without a clear added value, and information from signs is typically not in WGS84). The question is then how to name that tag: “local” sounded straightforward to me when I started using it, but if predominant usage is relative height (which we would have to find out), then that is not an option. --Stanton (talk) 16:08, 12 May 2020 (UTC)
I read discussion page about ele:local=* using machine translation and I have an impression that Krza, who wrote it, has no agreement with himself on how to use it and why use it at all. Maybe we should suggest to use something like ele:relative=* for marking relative elevations and use ele:local=* for local height system? --Dendik (talk) 09:26, 18 May 2020 (UTC)

Correct the wiki !

The present wording of the wiki is not reflecting the actual use of the ele=* tag. Users enter "on-the-ground" elevation values in the ele=* tag. They normally do not care about any reference system. In that sense the proposed ele:regional=* tag is functionlly describing the actual use of the ele=* tag. --voschix (talk) 10:56, 9 May 2020 (UTC)

The difference is that ele has all kind of reference, i.e. many may follow the ele:regional definition, while some are surely not and follow the longstanding definition for ele. You simply can’t tell for “ele”. —Dieterdreist (talk) 08:43, 10 May 2020 (UTC)
+1, ele=* is meant to be “elevation in WGS84”, but actual usage is “in whatever reference system the mapper chose”, with no indication of the reference system. OK for a rough indication, but insufficient if you need precise values. --Stanton (talk) 15:34, 12 May 2020 (UTC)

Good mess..

Glimpsed over the discussion in the mailing list with many smart posts. So my take is there might be:

  • ele:REFSYS where refsys might be one of NGVD29, NAVD88,...
    • ele:WGS84:geoid
    • ele:WGS84:ellipsoid
    • ele:WGS84:device
    • ele:WGS84:unknown
  • ele:regional : whatever is on signposts, in maps etc - and should be within 4 meters of ele:WGS84:geoid
  • ele - anything else, unknown, HOPEFULLY close to ele:regional

RicoZ (talk) 19:52, 12 May 2020 (UTC)

Unit

This proposal aims to tackle two different concepts in the same key: both the reference ellipsoid and the unit of measurement. I think it would be much more sensible to deal with units directly in ele=*. That's how countless other keys already work, like height=* and maxspeed=*. I've proposed that we relax the definition of ele=* to allow local units as long as they're explicitly specified. – Minh Nguyễn 💬 23:41, 28 November 2021 (UTC)