So you want to e.g. give the height of a bridge above the "mean high water spring" level of the river it crosses?
You wouldn't use a unit for that, but a qualifier. The unit would be meter (or feet or whatever).
The "elevation" property we have (P2044) is defined to refer to NN, so it's no good for your purpose. To model what you want nicely, you would need a more general "elevation" property, and a "reference level" property to use as a qualifier. Then you could express something like "elevation: 28.3m; reference-level: Q6803625".
I'm sure there are other options, but I see no good option that would be possible with the properties I know.
Anyway, this is really a modelling question, and it can't really be solved with units.
Am 27.09.2016 um 20:26 schrieb Markus Bärlocher:
Hallo Daniel,
nein, ich suche nicht einen WP-Artikel über MHWS, (diesen habe ich nur verlinkt als Erklärung)
sondern eine Einheit/unit, um MHWS als Bezugshorizont für geografische Höhen zu beschreiben.
MHWS wird verwendet, um Brückendurchfahrtshöhen über Wasser zu definieren, sowie für die geografische Höhe von Leuchtfeuern.
Mit herzlichem Gruss, Markus
Am 27.09.2016 um 19:28 schrieb Daniel Kinzler:
Am 27.09.2016 um 19:10 schrieb Markus Bärlocher:
I look for this: "Elevation in metres above 'mean high water spring' level."
Which means the geographic hight above MHWS: https://en.wikipedia.org/wiki/Mean_high_water_spring
By clicking on "Wikidata Item" in the sidebar of that page, I get to https://www.wikidata.org/wiki/Q6803625 ("highest level that spring tides reach on average over a period of time")
Is that what you need?
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