Hello Javier,

Disclosure: I'm a member of the subcommittee that maintains the EPSG registry. 
I also work for Esri.

I'm sorry that I took so long to respond. I haven't been keeping up with the 
list. My colleague, Bojan, had forwarded your message to me but it while I was 
on vacation and got buried. 

You can sometimes find information about why the subcommittee makes certain 
decisions in the Guidance Notes, https://epsg.org/guidance-notes.html

Guidance Note 7-6 is EPSG policies and procedures for EPSG Dataset data 
management, documents strategy for populating the EPSG Dataset. 

It includes a small section on extents with this bit about World extents: 

"There are two extent records for the whole world, code 2830 includes and code 
1262 excludes, the names of all countries. The description for 2830 is lengthy 
-- over 3000 characters. It is used for entities that might be wanted from a 
text string using country name. Code 1262 is used when a short description is 
appropriate." 

Do you feel we should expand the section or double-check that the choice of 
extent code is consistent? Feel free to ask me to bring it up to the 
subcommittee or send an email yourself using the online form at 
https://epsg.org/contact.html.

It's also tied to an option you have when logged in, "Include World Items". We 
recently discussed whether to move more objects in/out of that category like 
the ITRF definitions.

Regards,
Melita

-- 
Melita Kennedy
Principal Product Engineer
Esri, Inc.
[email protected]

======================================================


From: PROJ <[email protected] (mailto:[email protected])> 
On Behalf Of Even Rouault via PROJ
Sent: Saturday, December 30, 2023 11:18 AM
To: Javier Jimenez Shaw <[email protected] (mailto:[email protected])>; 
proj <[email protected] (mailto:[email protected])>
Subject: Re: [PROJ] World area of use

Hi Javier,
I don't know the reason for the difference, but if there's one, it would be 
interesting to know, and if there's none, converging to World (without country 
list, extent 1262) would indeed seem better. Looking at the few instances that 
use World by country (extent 2830), there is no apparent logic. It isn't even 
related to the type (geographic 2D vs 3D vs geocentric).
Grep'ping in the change items of the registry (grep epsg_change 
PostgreSQL_Data_Script.sql | grep 1262 | grep 2830), shows a global trend of 
moving from 2830 to 1262 (with a interesting back &amp; forth for CRS 8227, 
IGS14 geocentric, which was changed from 1262 to 2830, and then later back to 
1262)
Even
Le 30/12/2023 &agrave; 19:54, Javier Jimenez Shaw via PROJ a &eacute;crit :
Hi

Playing with crs-explorer, I found that there are a few (and only a few) CRSs 
with an endless "area of use" description:
?latlng=-45.435465,-15.468750&amp;ignoreWorld=false&amp;allowDeprecated=false&amp;authorities=EPSG&amp;activeTypes=GEOGRAPHIC_2D_CRS,GEOGRAPHIC_3D_CRS,GEOCENTRIC_CRS
 [crs-explorer.proj.org] 
(https:/crs-explorer.proj.org/?latlng=-45.435465,-15.468750&amp;ignoreWorld=false&amp;allowDeprecated=false&amp;authorities=EPSG&amp;activeTypes=GEOGRAPHIC_2D_CRS,GEOGRAPHIC_3D_CRS,GEOCENTRIC_CRS
 
(https://urldefense.com/v3/__https:/crs-explorer.proj.org/?latlng=-45.435465,-15.468750&amp;ignoreWorld=false&amp;allowDeprecated=false&amp;authorities=EPSG&amp;activeTypes=GEOGRAPHIC_2D_CRS,GEOGRAPHIC_3D_CRS,GEOCENTRIC_CRS__;!!CKZwjTOV!2uziJJtS5R3htvY33qmdDN1rJ-yl23YUiU7NAtFcJgQ3laCDfCl5lFah7a66_RTDPzQIdD-o6GRn$))

In EPSG called "World (by country)" World-by-country.html [epsg.org] 
(https:/epsg.org/extent_2830/World-by-country.html 
(https://urldefense.com/v3/__https:/epsg.org/extent_2830/World-by-country.html__;!!CKZwjTOV!2uziJJtS5R3htvY33qmdDN1rJ-yl23YUiU7NAtFcJgQ3laCDfCl5lFah7a66_RTDPzQIdPBiEOeG$))

like
EPSG:4326 [epsg.org] (https:/epsg.org/crs_4326/WGS-84.html 
(https://urldefense.com/v3/__https:/epsg.org/crs_4326/WGS-84.html__;!!CKZwjTOV!2uziJJtS5R3htvY33qmdDN1rJ-yl23YUiU7NAtFcJgQ3laCDfCl5lFah7a66_RTDPzQIdJmPB8XQ$))
WGS 84
EPSG:9754 [epsg.org] (https:/epsg.org/crs_9754/WGS-84-G2139-.html 
(https://urldefense.com/v3/__https:/epsg.org/crs_9754/WGS-84-G2139-.html__;!!CKZwjTOV!2uziJJtS5R3htvY33qmdDN1rJ-yl23YUiU7NAtFcJgQ3laCDfCl5lFah7a66_RTDPzQIdBTV_bnb$))
WGS 84 (G2139)


EPSG:9988 [epsg.org] (https:/epsg.org/crs_9988/ITRF2020.html 
(https://urldefense.com/v3/__https:/epsg.org/crs_9988/ITRF2020.html__;!!CKZwjTOV!2uziJJtS5R3htvY33qmdDN1rJ-yl23YUiU7NAtFcJgQ3laCDfCl5lFah7a66_RTDPzQIdEgAvj6T$))
ITRF2020


EPSG:10176 [epsg.org] (https:/epsg.org/crs_10176/IGS20.html 
(https://urldefense.com/v3/__https:/epsg.org/crs_10176/IGS20.html__;!!CKZwjTOV!2uziJJtS5R3htvY33qmdDN1rJ-yl23YUiU7NAtFcJgQ3laCDfCl5lFah7a66_RTDPzQIdAY_9M5R$))
IGS20

but not some other implementations like
EPSG:4978 [epsg.org] (https:/epsg.org/crs_4978/WGS-84.html 
(https://urldefense.com/v3/__https:/epsg.org/crs_4978/WGS-84.html__;!!CKZwjTOV!2uziJJtS5R3htvY33qmdDN1rJ-yl23YUiU7NAtFcJgQ3laCDfCl5lFah7a66_RTDPzQIdOxjP9Ib$))
WGS 84
EPSG:9753 [epsg.org] (https:/epsg.org/crs_9753/WGS-84-G2139-.html 
(https://urldefense.com/v3/__https:/epsg.org/crs_9753/WGS-84-G2139-.html__;!!CKZwjTOV!2uziJJtS5R3htvY33qmdDN1rJ-yl23YUiU7NAtFcJgQ3laCDfCl5lFah7a66_RTDPzQIdDXobqfV$))
WGS 84 (G2139)


EPSG:9055 [epsg.org] (https:/epsg.org/crs_9055/WGS-84-G1150-.html 
(https://urldefense.com/v3/__https:/epsg.org/crs_9055/WGS-84-G1150-.html__;!!CKZwjTOV!2uziJJtS5R3htvY33qmdDN1rJ-yl23YUiU7NAtFcJgQ3laCDfCl5lFah7a66_RTDPzQIdBVfUA7V$))
WGS 84 (G1150)

(yes, same CRS. The difference is Geographic 2D vs 3D vs geocentric)

Do you know why this difference?
Is it something to communicate to EPSG?
I personally think that that endless list of countries is not needed when there 
is a "World" at front.

Cheers and happy new year.
.___ ._ ..._ .. . ._. .___ .. __ . _. . __.. ... .... ._ .__

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