Thank you for turning me on to Atlas Obscura! I downloaded the app, and have already marked several places I want to visit, and others that I've been to. Looking forward to working with it more!
I happened to have been in Thailand recently, and came across these statues holding up traffic lights. I found it fascinating that a city council would devote resources to something like this. I'm looking forward to seeing other treasures that Atlas Obscura has.
I still don't quite get it. So the center is the barycenter of the planet, but that only gives you the point, not the axes.
The Z axis seems the most clearly defined as it's just aligned to the planet's rotation and the XY plane could be defined as just halving that, but the the rotation of the XY plane doesn't seem to be well defined. The article seems to fix it to the first meridian which is a land reference and subject to drift, so it would be inaccurate. Or there'd be some reference point in the south atlantic where the drift is zero and the rest is relative to it?
Further along this line of discussion, it's always been immensely puzzling to me how sun-relative solar system localization systems handle this sort of thing, since while it's possible to locate the sun and a few stars to track your absolute rotation and one translational axis, where the hell do they get the other two? One reference might be Earth signals I suppose, and possibly Jupiter? But they are all coplanar so the Z axis resolution from triangulation must be complete crap.
The IERS reference median is “the weighted average (in the least squares sense) of the reference meridians of the hundreds of ground stations contributing to the IERS network” [1].
> WGS 84 is a global standard tied to no one plate. In essence, it is fixed to Earth’s deep interior.
Those drift vectors are based on GPS, which the article also says relies on WGS 84z