We propose that mental representations of extrapersonal space are largely determined by the information that is required for actions within that space. Three different aspects of mental representations of space are briefly discussed. First, the physical size of a space restricts the set of behaviors that can be performed within the space. Mental representations of space therefore should differ in important respects depending on the perceived physical size of the referent space. Second, different reference systems can be used to code spatial information. Third, the demands on accuracy of representing spatial information differ between tasks. We posit that specialized mental representations are best suited to accomodate the different demands posed by actions within a given space. The benefit of different formats of mental representations, especially of analog representation, is addressed from a theoretical perspective. We argue that although different representational systems can be constructed that possess similar behavioral characteristics, analog representations in some cases lend themselves to more directly testable predicitions than other representations.