[PROJ] World area of use

Wed Jan 31 06:07:37 PST 2024

Thanks Melita

That shows that there is some intention there, not just two extents used
randomly (that was the impression).
Me personally I would use always the "short" extent, 1262. The long list of
all countries is redundant and extremely verbose for me.

Best regards,
Javier.

On Tue, 30 Jan 2024 at 19:58, Melita Kennedy via PROJ <proj at lists.osgeo.org>
wrote:

> 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.
> mkennedy at esri.com
>
> ======================================================
>
>
> From: PROJ <proj-bounces at lists.osgeo.org (mailto:
> proj-bounces at lists.osgeo.org)> On Behalf Of Even Rouault via PROJ
> Sent: Saturday, December 30, 2023 11:18 AM
> To: Javier Jimenez Shaw <j1 at jimenezshaw.com (mailto:j1 at jimenezshaw.com)>;
> proj <PROJ at lists.osgeo.org (mailto:PROJ at lists.osgeo.org)>
> 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 & forth for CRS
> 8227, IGS14 geocentric, which was changed from 1262 to 2830, and then later
> back to 1262)
> Even
> Le 30/12/2023 à 19:54, Javier Jimenez Shaw via PROJ a écrit :
> 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&ignoreWorld=false&allowDeprecated=false&authorities=EPSG&activeTypes=GEOGRAPHIC_2D_CRS,GEOGRAPHIC_3D_CRS,GEOCENTRIC_CRS
> [crs-explorer.proj.org] (https:/
> crs-explorer.proj.org/?latlng=-45.435465,-15.468750&ignoreWorld=false&allowDeprecated=false&authorities=EPSG&activeTypes=GEOGRAPHIC_2D_CRS,GEOGRAPHIC_3D_CRS,GEOCENTRIC_CRS
> (
> https://urldefense.com/v3/__https:/crs-explorer.proj.org/?latlng=-45.435465,-15.468750&ignoreWorld=false&allowDeprecated=false&authorities=EPSG&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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