XnView Software

These are my settings for browser tooltips (see last line GPS {Exif latitude} {Exif longitude} ) And that is diisplayed : For locations west of the Greenwich meridian, a minus sign must be added

In the browser -3°-34' -59.35 is displayed, -3°34' 59.35 would be better
in the Tooltip , wrong value 3°34' 59.35 is diplayed instead of -3°34' 59.35

Dans les info-bulles, le signe moins est manquant
Dans le browser, en il y a des signes moins en trop ...

Thanks to your detailed description I can reproduce

I wanted to know, is it possible to regularily change the GPS coordinates as you're moving around? My job requires me to go abroad quite often, and on top of that, I was thinking of scoring one of these houses in Greece for the holidays... So, I'd need to change it several times a year.

Thanks in advance!

Some cameras contain a GPS receiver, and they automatically record the coordinates in each photo (embedded exif gps data)
Most smartphones also have a GPS receiver, and if you enable it, the photos will also have the coordinates.

If you can not use any of these methods, you will have to use a software like Geosetter to geotag your photos later, or search coordinates in google maps, and paste them in "Tools, Metadata, Edit GPS"
Another way is to record GPS logs ? (French : Trace GPS) in a GPX file, and synchronize locations using timestamps of photos (with some other softwares)

https://en.wikipedia.org/wiki/GPS_Exchange_Format

Roger, thanks for the quick answer and for the plethora of options! Now, I'm sure I'll master at least one of them!

See issue for current status and some details.

This problem is supposed to be fixed in XnView MP 0.96. Please check and confirm the bug fix here.

V0.96
Details view is now correct.
In tooltips, as suggested by Pierre, I added latitude ref and longitude ref, so the result is nice !

If someone needs to copy coordinates, use the new feature in Tools, Metadata, Edit GPS" ...

Solved !
Thanks !!