Question: Which film, directed by Roger Christian is based upon the first half of L. Ron Hubbard's 1982 novel of the same name? 
Sentence (from "Battlefield Earth (film)"): Battlefield Earth (also referred to as Battlefield Earth: A Saga of the Year 3000) is a 2000 American science fiction action film based upon the first half of L. Ron Hubbard's 1982 novel of the same name.
Relevant evidence: Yes