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EPSG and MGA definitions

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The EPSG registry (v9.0) now clearly defines the distinction between GDA94 and GDA2020, however the UTM projections (projected CRS) of these geodetic CRS (MGA94 and MGA2020) are potentially ambiguous in the registry with a preference to adopt ISO projection naming conventions e.g. MGA94 zone xx is GDA94 / MGA zone xx and MGA2020 zone xx is GDA2020 / MGA zone xx. As GDA94 and GDA2020 are fundamentally two different datums (not a revision as inferred by the ISO convention) shouldn't the projected CRS carry the full MGA94 or MGA2020 qualification? This would remove any uncertainty regarding the parent geodetic CRS of MGA data when using a GIS. The use of GDA or MGA without the 94 or 2020 qualification is not desirable at all considering that the datums are different by less than 2 metres.

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Thanks Quickclose,

The conventions that are applied to both GDA94 and GDA2020 and their respective projected coordinate reference system follow the standard set out in ISO 19127 (see section C.7 Element Naming, C.7.8 Projected coordinate reference systems).  It was advised by the EPSG to follow this approach so as not to unnecessarily create 15 new map projections for the Map Grid of Australia that are no different to the existing ones used for GDA94.   Hence the naming convention within the EPSG is GDA2020 / MGA Zone xx.

Nevertheless, the new GDA2020 Technical Manual will define GDA2020 grid coordinates as Map Grid of Australia 2020 (MGA2020).

I hope this makes it clear, but please repost if you need more help.

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Thank you Dan,

Maybe it would be possible for our local usage (which EPSG suggests is inconsistent with the ISO standard) to be registered as an alias name in the EPSG Registry. This way, someone doing a search for MGA2020 will be directed to right registry entry. My only concern is someone importing MGA94 or MGA2020 data into their GIS will not see "MGA94" or "MGA2020" if the GIS parameters are sourced directly from the EPSG registry. What we are trying to avoid is inconsistency with projection naming.

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