[PROJ] Pitching the proj project to Google's Geo team

[Martin Desruisseaux]

Le 22/08/2022 à 17:05, Lesparre, Jochem via PROJ a écrit :

> I support:
>
>   *  (…snip…)
>   * Greg’s suggestion to stop using WGS84 (EPSG:4326).
>
Just one nuance about above last point. I agree about deprecating 
EPSG:4326 for /data producers/ (i.e. encourage all data producers to 
describe their CRS as accurately as they can). But we still need 
EPSG:4326 as an ensemble (i.e. with its ~2 meters uncertainty) for /data 
users/. The reason is that when a software reads a file from unknown 
source, if the CRS has not been accurately defined by the producer, 
there is nothing the software or user can do about that. In those cases, 
the worst thing would be to /pretend/ that we have a CRS of some 
specific realization while actually the software has no idea. We need a 
way to said "we don't know what is the realization because the producer 
did not tell us, expect a 2 meters uncertainty".

So I would not be in favour of interpreting EPSG:4326 as the latest 
realization. I think it should continue to mean "we don't know the 
realization", and every coordinate transformation involving EPSG:4326 
should declare a 2 meters uncertainty. We need to keep the possibility 
to said "we don't know", even if we want to encourage data producers to 
be more accurate.

     Martin

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20220822/261875f6/attachment.htm>