Talk:Tag:type=benchmark

How it is supposed to be used?

Since creation it was marked as unusable on nodes Mateusz Konieczny (talk) 16:40, 3 January 2021 (UTC)

Don't use this. It's redundant to Tag:survey_point:purpose=vertical (if it's actually a benchmark, a triangulation point is Tag:survey_point:purpose=horizontal). Revent (talk) 20:27, 10 April 2022 (UTC)

Actually benchmark is only one form of vertical control. Not all vertical control markers can be considered as a benchmark, I believe. You can further have local markers. It has more information than survey_point:purpose=vertical, however you can argue this is ambiguous (should be elaborated). Also possible to have some (perhaps electronic ones, though not sure if they are called "benchmark" proper) for both horizontal and vertical.

That proposal doesn't handle these other attributes. datum_aligned=* only says whether it is aligned, not what it is. Although most benchmarks should be, unless they are somehow moved, not re-established yet.

--- Kovposch (talk) 09:23, 11 April 2022 (UTC)

Likely a wiki editing error. survey_point=benchmark (49 instances at least) is a possible alternative, now that survey_point:structure=* is available.

survey_point=benchmark

		$1%
		$1%
		$1%
		$1%

More details at taginfo

More details at taginfo

-- Kovposch (talk) 09:25, 11 April 2022 (UTC)

@Kovposch TBH, these days, if it's actually been surveyed by GPS and the coordinates are available (on the NGS datasheet, or a local government website) then it's effectively "both" regardless of how it's actually monumented, though things like "Height Modernization Survey" ones (that are a steel rod driven to refusal) should probably be called vertical. I think the structure tag (what is actually there in the ground) is a good way to differentiate.

As far as the datum, I have used Tag:survey_point:datum and Tag:survey_point:datum:epoch (when it mattered) when actually converting precise coordinates from something else to WGS84. The NGS datasheets actually tell you if a monument has been reported as disturbed. Revent (talk) 21:59, 22 June 2022 (UTC)