Humans may dwell here

If you're talking about armor, then no.

I'm talking about earth and ice shields.

The range is infinite; you just need to see the target.

So, can I sit in some room in the middle of nowhere, observe my companions through a mage's eye, and heal them?

Light armor gives a small resistance of 5-15%, medium armor gives resistance of 25% + some types block a fixed amount of damage, heavy armor always blocks damage by a fixed amount, approximately 50, but it doesn't block completely; 2 units of damage always get through.

Does armor only block physical damage, or does it block physical and magical damage, or physical damage and some types of magical damage (for example, damage from icicles and earth fists is reduced, but damage from lightning and "intangible" types of damage is not)?