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Comment by defrost

1 day ago

Magnetic, rotational, geodetic .. ?

What are you trying to say?

Can there even be geodetic drift of the poles? I sort of assumed that our lat/lon system is based on the poles being fixed points as a matter of definition.

  • Each ellipsoid is rigidly defined (well, some historic ones are sloppy), so WGS84 won't drift .. (that's a bold statement, is it true down to the micron and if so what are the absolute* datums to reference against?).

    That said, there are literally hundreds of historic pre WGS84 ellipsoid|datum pairings, each with a somewhat different "survey map pole".

    Historically geodectic poles have shifted as a function of datums.

    The main point here, such as it is, was to poke at the infomation free aspect of "polar drift" as a comment .. which pole and what does that have to do with climate change? etc.

    • We still use many of those old ellipsis and datum’s today. When you’re doing human things, like surveying land, and defining property boundaries. It’s nice to work with a coordinate system which remains fixed relative to the area you’re surveying, and doesn’t drift due to annoying things like tectonic movement, or your entire country slowly tipping into the ocean.

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