The correct answer is: There are other ways to use place.
Indeed, the author begins his phrase by stating that “another” way to tap the imagination is place. This implies that just as there are other ways to tap imagination; there are other ways to use place. Not all authors consider place as something as important as “the richest character in human form”. There are several who focus more on characters or even on different forms of narration. For many authors place is just a setting that may convey some meaning or not. Nevertheless, many of the best novels pay special attention to place as it can be used profusely to mirror the protagonist’s state of mind or to further emphasize it by contrast.
A notion associated with place is the pathetic fallacy, for example: a character who has just lost his beloved wife and who walks aimlessly in a dark forest during a lightning storm and who feels that nature is mourning the death of this wife with him.