Some great research you present here StephaneP. Thanks.

Us Australians are wrestling with upcoming misaligned maps in web-mapping because we have: * GDA2020 is defined as having moved 1.8 from GDA94 * GDA94 is defined the same as WGS84 (which was the case in 1994) * GDA2020 is defined as the same as WGS84 (which will be the case in 2020) * Web-mapping use cases incorrectly assumes WGS84 hasn’t changed.

We are discussing on the proj email list: https://lists.osgeo.org/pipermail/proj/2019-July/thread.html thread: [PROJ] Static/Dynamic Webmapping Problem version 2.0

I’ve been drafting a positional paper - covering many of the same concepts: https://docs.google.com/document/d/15uBX2qICODRkiHXeksT0zEy6TuysanIxuc4anV0o5F0

I’m expecting that our solution will involve creating an EPSG code for a static realisation of WGS84 which aligns with existing proj transformations within each region and epochs.