`proj -V` swaps x and y annotations for some polar projections

[zqianem]

Example of problem

When running the proj command with -V, projections centered on the poles such as EPSG:3413 output the wrong annotations for x and y.

The values are in the correct order, only the annotations are swapped — it should be Easting (x) first:

echo -45 71 | proj -V EPSG:3413

...
Northing (y):  0.00
Easting (x):   -2076527.85
...

Problem description

I suspect this is caused by proj internally using the WKT2 representation of EPSG:3431 and then proj -V misinterpreting the first axis as a north-south axis because its direction is technically south (since everything is south of the North Pole), even though the actual axis is an easting:

projinfo EPSG:3413 | grep -A 10 CS

    CS[Cartesian,2],
        AXIS["easting (X)",south,
            MERIDIAN[45,
                ANGLEUNIT["degree",0.0174532925199433]],
            ORDER[1],
            LENGTHUNIT["metre",1]],
        AXIS["northing (Y)",south,
            MERIDIAN[135,
                ANGLEUNIT["degree",0.0174532925199433]],
            ORDER[2],
            LENGTHUNIT["metre",1]],

The same issue also appears to happen with other polar projections such as EPSG:3031:

echo 0 -71 | proj -V EPSG:3031

Expected Output

The expected output can be generated if we use the PROJ4 string representation of EPSG:3413 as it does not have any axis information:

echo -45 71 | proj -V +proj=stere +lat_0=90 +lat_ts=70 +lon_0=-45 +x_0=0 +y_0=0 +ellps=WGS84

...
Easting (x):   0.00
Northing (y):  -2076527.85
...

Environment Information

• PROJ Rel. 9.6.0, March 15th, 2025
• ArchLinux

Installation method

• pacman