A map data is disclosed. The map data comprises a link data and a segment data. The link data describes a characteristic of each link in a group of links on a link-by-link basis. The group of links forms a road network. The segment data relates to each segment in a group of segments on a segment-by-segment basis. The segments are defined in units of link string. Each link string is a string of multiple links and corresponds to a main road. Each link string terminates at least at an intersection of the main road. The multiple links are a part of the group of links. The segment data of each segment describes information on a storage destination of the link data corresponding to the link string that forms the each segment.