Fair isle yarns are carried around the entire garment and are more for creating and entire overall pattern. It can be done flat, but it's more of a pain to carry the yarns across the back I think.
Intarsia is usually use for larger blocks of color like in picture and is done flat. There are some fiddly methods if doing it in the round, but you'll have to check you tube.
Both techniques have videos in KH under advanced techniques.