Similarities to Dune by Frank Herbert.

[HarryCanyon]

Since Cameron wrote the film in 1993, he stated that one of the influences was Frank Herbert's Dune which is one of his favorite books of all time.

I'm a fan of Avatar and Dune myself and you'll find similarities.

Both have heroes that left their planets to live on that new planet which is exotic and unique.
Crap hits the fan when their relatives died.
Both become outcasts and join up with a tribe of warriors that have prophecized a man would come be their leader.
Both have similar love interests.
Both the Baron and Quatrich are the same.
Both tame the wild beasts and go through tests of manhood.
Both tribes have other tribes to fight against the corporation.
And that kind of thing.