When a novel transitions into the big screen, it is only natural that some artistic liberties will be taken. Otherwise, there wouldn't be much point in seeing the movie if it was exactly the same as the novel. After all, regular novels are noteworthy because of their rich and expansive worlds, unrestrained by the limits of time and space. In the case of fantasy novels, imagination does almost all the work.
The 10 Most Important 'The Lord of the Rings' Book Characters Not in the Movies
You shall not pass... into live-action.