[PROJ] World UTM in a proper datum

[Noel Zinn (cc)]

We really need two codes, don’t we?  One for the geographical datum (ITRF2014 in GRS80, which is EPSG:7789 in your case) and one for the projection UTM in GRS80 (which, I guess, doesn’t exist), perhaps an EPSG architecture problem.  To be frank, your expectation that the EPSG do for ITRF2014 what it’s done for WGS84/UTM is unrealistic.  Add ITRF2008 and so on, how many combinations would that be?


From: Javier Jimenez Shaw 
Sent: Saturday, April 17, 2021 3:56 PM
To: Noel Zinn (cc) 
Cc: proj 
Subject: Re: [PROJ] World UTM in a proper datum

Hi Noel, 
If I am the only user of the data, I can do that (and whatever I want). But if I have to produce accurate data processed by somebody else, I fall into the hole of vagueness of WGS84. For instance, if I create a precise GeoTIFF and I want to tag it with an EPSG, using EPSG:326XX is... vague. Or a GCP, or anything else. There are several alternatives for the geographic crs.
I know I can apply UTM over ITRF2014 (GDAL does it easily). But there is no EPSG code for that.

.___ ._ ..._ .. . ._.  .___ .. __ . _. . __..  ... .... ._ .__
Entre dos pensamientos racionales 
hay infinitos pensamientos irracionales.




On Sat, 17 Apr 2021 at 22:24, Noel Zinn (cc) <ndzinn at comcast.net> wrote:

  Unlike an empirically-derived datum transformation (e.g. WGS <> ITRF), which can have different levels of "accuracy" depending how it was derived, a map projection (lat/lon <> N/E) is defined mathematically and is precise, i.e. without error.  Having said that, there are better and worse algorithms for UTM, but that's not the question you're asking.  In a datum transformation sense UTM will always be as (and only as) "accurate" as the geographicals you convert to N/E.  So, use EPSG:326XX and EPSG327XX, but plug in your precise geographicals.  


  From: Javier Jimenez Shaw 
  Sent: Saturday, April 17, 2021 2:44 PM
  To: proj 
  Subject: [PROJ] World UTM in a proper datum

  Hi 

  Maybe there is a better place to talk about this, but I do not know which one. I hope somebody from EPSG is reading this, and may give me a clue.

  We have talked many times about the lack of accuracy of WGS84 (EPSG:4326), the datum ensemble, etc.
  The problem is that I miss an accurate equivalent of the projected family "WGS84 / UTM zone XXY"(EPSG:326XX and EPSG327XX) for XX between 1 and 60 and Y is N or S. It would be nice something similar (a worldwide projected CRSs on UTM), but over a proper accurate and well defined geographic CRS (ITRF2014, WGS84(G1762), etc).

  Do you know if there is any plan? Or do they exist and I was not able to find them?

  Thanks.

  .___ ._ ..._ .. . ._.  .___ .. __ . _. . __..  ... .... ._ .__
  Entre dos pensamientos racionales 
  hay infinitos pensamientos irracionales.



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