Yes, you're quite right. Here's an article on how Cameron also plagiarised author Poul Anderson's Call me Joe. It seems Cameron has borrowed from a few sources.
Funnily enough, these stories from Poul Anderson and Arkady and Boris Strugatsky are regarded as great works of science fiction, but when these same stories are merged into Avatar, we have people on this forum who say the story is:
"An inane Pocahontas story", "From all descriptions the story is as cliche, trite, and preachy as it can get mushed up by some lame love story", "The story is cliche and very predictable", "it very much comes across as cliche, trite, and preachy", "Predictability/cliche etc", "goofy looking aliens and two and a half hours of dances with wolves/pocahontas storyline ", etc