When we navigate, we usually use perceptual information, a series of vista accompanying the navigation. Probably most of everyday navigation are correctly accomplished by recognizing a series of vista. On the contrary, when we communicate geographical information to others, that is, when we tell others the way to some place, we use something other than perceptual information as well. These forms of describing environments do not originate directly from real navigation. What does such a form come from? When we communicate geographical information of an environment to those who are away from it, e.g., when we tell someone the way to some place by phone or letter, we often use a form of map represented from a bird'seye view. Such facts suggested in the background of a specific form of representing geographical information may exist a special form of social communication, which may have promoted the use of such a form of representation.