Citerar Mark Sims <[email protected]>:
In the standards definitions that include "at sea level", the
question these days is "which sea level?". As ocean temperature
changes sea level will change (except maybe in Washington DC). Will
the standards be amended to include something like "at sea level in
1990" or will the value being defined drift around with the changing
sea level?
From the current Swedish vertical datum.
(http://www.lantmateriet.se/globalassets/kartor-och-geografisk-information/gps-och-matning/geodesi/rapporter_publikationer/rapporter/lmv-rapport_2007_4.pdf)
"This realisation was made using the Normaal Amsterdams Peil (NAP)
as zero level
in the traditional European way. [...] It has for instance been
questioned whether NAP is the most suitable way to fix the
zero level. Is it not better to wait for a so-called World Height
System (WHS), which is fixed using GPS and a global geoid model of cm
accuracy?"
Has the World Height System been agreed/released?
http://www.euref.eu/documentation/Tutorial2015/t-04-02-Ihde.pdf
Picture showing reference origin for vertical datums in Europe.
https://en.wikipedia.org/wiki/File:Vertical_references_in_Europe.svg
--
Björn
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