Hi Daniel,
So you want to e.g. give the height of a bridge above
the "mean high water
spring" level of the river it crosses?
Yes.
use a qualifier. The unit would be meter
Yes.
The "elevation" property we have (P2044) is
defined to refer to NN
It is not a good idea, to define 'elevation'
like it is "defined" in P2044:
there are hundreds of reference-levels (not only NN)...
NN was used from 1879 to 1992 in Germany.
Now in Germany we use NHN !
In other countries there are different reference levels
changing in different epoches ...
you would need a more general "elevation"
property,
and a "reference level" property to use as a qualifier.
Yes, every elevation needs a reference level.
(without a elevation measurement is not usable)
Then you could express something like "elevation:
28.3m;
In WD there is a confusion between altitude and elevation?
(may be in American and British English?
or geographic and aviation and astronomy?)
reference-level: Q6803625".
_reference-level_ could be:
'NN'
'NHN'
'LAT'
'MSL'
'MHWS'
and a lot of others...
But this is a combination of unit and reference-level:
'm ü.M.'
We should not mix or confound this modellings...
What will be the WD-way?
(you should discuss this with a geodetic specialist...!)
Additionally we need an expression for 'accuracy' and 'source':
If the hight unit is 'meter' and the source value is in 'feet',
the new value could have a lot more/less digits than the source,
but no better/worse accuracy...
Bests, Markus
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?