RE: [WCS.RWG] Thoughts on GALEON Phase 2

Notably, a grid can have any subset of these axes - for example, x/z cuts appear in geophysics.

And are implemented, for example, in our test WCS at
http://glue.badc.rl.ac.uk/cgi-bin/TPAC/WCS.

But not only WCS - these type of slices are also possible (in principle)
for WMS, though I've seen no implementations (though TPAC is continuing
our WCS work to the WMS case.)