Why some CRS are deprecated in QGIS?

Question

I tried to specify the Pulkovo 1942 / Gauss-Kruger 13N (EPSG:28473) CRS for my QGIS project. But it is deprecated. I have never seen such issue before.

Why it is deprecated?

The QGIS version is 3.6.3

Answer 1

EPSG:28473 is deprecated in the EPSG database in 2002. The corresponding change request is https://epsg.org/closed-change-request/browse/id/2002.36 and the reason for the request was "Rationalise Gauss-Kruger zone names"

The new code to use is EPSG:2503 https://epsg.org/crs_2503/Pulkovo-1942-Gauss-Kruger-CM-75E.html

Answer 2

In this case because of a

Change of CRS name to indicate longitude of origin.

As stated in the link you provided, this is a registry decision (see @user30184's answer) rather than a software internal state or issue. QGIS only reads out properties from the proj registry library; i.e. the OGC WKT representation of this CRS:

PROJCS["Pulkovo 1942 / Gauss-Kruger 13N (deprecated)",GEOGCS["Pulkovo 1942",DATUM["Pulkovo_1942",SPHEROID["Krassowsky 1940",6378245,298.3,AUTHORITY["EPSG","7024"]],AUTHORITY["EPSG","6284"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4284"]],UNIT["metre",1,AUTHORITY["EPSG","9001"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",75],PARAMETER["scale_factor",1],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],AUTHORITY["EPSG","28473"],AXIS["Y",EAST],AXIS["X",NORTH]]

Note that you are supposed to

Use EPSG:2503 instead.

Answer 3

Update from January 2024

Spatialreference.org is now maintained and updated alongside PROJ development 🎉!

---

Original/old answer

A caution to folks still using spatialreference.org :

It is not maintained, with the last update in 2013.

Use a modern source, including:

1. The official EPSG registry: https://epsg.org
2. A recent version of PROJ, e.g., see the output from projinfo EPSG:28473
3. Or a slightly less out-of-date third party resource http://epsg.io/28473 (see EPSG database version at the bottom of web page)