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A comment on How Crossrail was affected by the curvature of the Earth (2018). Parent comment

Re:How Crossrail was affected by the curvature of the Earth ... by lmc on Thursday May 05, 2022 @12:58PM (#31275820)
> the extra computation to do everything in WGS-84 space is insignificant

There is still significant overhead involved in conversion - arbitrary trig functions, even optimised, are still really expensive compared to planar geometry. Remember these folks will be working at super high resolutions too.

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Re:How Crossrail was affected by the curvature of the Earth ... by iggldiggl on Friday May 06, 2022 @04:10AM (#31282649)
Isn't another issue also that WGS-84 is fixed globally, which'd mean that due to continental drift, local coordinates would be constantly shifting? Whereas the current local grids are usually fixed with regards to the local continental plate, so coordinates remain relatively stable-ish because the whole local grid moves together with the continental plate.
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Re:How Crossrail was affected by the curvature of the Earth ... by lmc on Friday May 06, 2022 @02:34PM (#31288380)
I was thinking about mentioning that... yes! Construction on this project began 13 years ago so it needs to be taken into consideration. A similar project in Australia would've seen a drift of up to several metres in this time [0]. Europe has another angular CRS for this reason [1].

[0]: https://theconversation.com/australia-on-the-move-how-gps-ke...

[1]: https://www.killetsoft.de/t_1009_e.htm

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