An information processing method for displaying map data comprising the steps of: displaying a geographical map comprising a plurality of building icons or a floor map comprising a plurality of different floors, wherein said map data of both said geographical and floor maps are stored in a plurality of map data files comprising file names and map image data; creating a file name constituted by an identification code for identifying either a map structure of a geographical map or a building and a floor of a floor map, a level code for denoting a scale level of the map, and by unit codes for indicating which part of said area is covered by said map; and reading map image data from one of said map data files having said file name; controlling display of maps based on said map image data, wherein if: a scroll operation is designated to bring about scrolling from a first map of which display is controlled, to a second map adjacent to said first map and having the same scale level as said first map, then said creating means creates said file name by either incrementing or decrementing by 1 a value in a bit position corresponding to said level code in each of said unit codes; or a zoom-out operation is designated to bring about a transition of display from a first map of which display is controlled, to a second map on a smaller scale including a specific part of said first map, then said creating means creates said file name by masking a value in a bit position corresponding to said level code in each of said unit codes; or a zoom-in operation is designated to bring about a transition of display from said first map to a third map on a larger scale including said specific part of said first map, then said creating means creates said file name by substituting a predetermined value for the value in said bit position corresponding to said level code in each of said unit codes. displaying a geographical map comprising a plurality of building icons or a floor map comprising a plurality of different floors, wherein said map data of both said geographical and floor maps are stored in a plurality of map data files comprising file names and map image data; creating a file name constituted by an identification code for identifying either a map structure of a geographical map or a building and a floor of a floor map, a level code for denoting a scale level of the map, and by unit codes for indicating which part of said area is covered by said map; and reading map image data from one of said map data files having said file name; controlling display of maps based on said map image data, wherein if: a scroll operation is designated to bring about scrolling from a first map of which display is controlled, to a second map adjacent to said first map and having the same scale level as said first map, then said creating means creates said file name by either incrementing or decrementing by 1 a value in a bit position corresponding to said level code in each of said unit codes; or a zoom-out operation is designated to bring about a transition of display from a first map of which display is controlled, to a second map on a smaller scale including a specific part of said first map, then said creating means creates said file name by masking a value in a bit position corresponding to said level code in each of said unit codes; or a zoom-in operation is designated to bring about a transition of display from said first map to a third map on a larger scale including said specific part of said first map, then said creating means creates said file name by substituting a predetermined value for the value in said bit position corresponding to said level code in each of said unit codes. a scroll operation is designated to bring about scrolling from a first map of which display is controlled, to a second map adjacent to said first map and having the same scale level as said first map, then said creating means creates said file name by either incrementing or decrementing by 1 a value in a bit position corresponding to said level code in each of said unit codes; or a zoom-out operation is designated to bring about a transition of display from a first map of which display is controlled, to a second map on a smaller scale including a specific part of said first map, then said creating means creates said file name by masking a value in a bit position corresponding to said level code in each of said unit codes; or a zoom-in operation is designated to bring about a transition of display from said first map to a third map on a larger scale including said specific part of said first map, then said creating means creates said file name by substituting a predetermined value for the value in said bit position corresponding to said level code in each of said unit codes.