1. An abridged map generating apparatus, comprising: a polygon shape data extraction unit that extracts from map data polygon shape data specifying shapes of polygons corresponding to a shoreline, pond, lake or river; an integration unit that integrates a part of a polygon and a part of a road which are mutually adjacent and creates an integrated link for indicating the both parts of the polygon and the road by common data; a polygon shape simplification unit that simplifies shapes of the polygons based upon the polygon shape data which is extracted by the polygon shape data extraction unit; an integrated link shape simplification unit that simplifies a shape of the integrated link created by the integration unit; a separation unit that separates the integrated link whose shape is simplified by the integrated link shape simplification unit into a polygon separation link and a road separation link; and a drawing unit that draws upon a map the polygons whose shapes have been simplified by the polygon shape simplification unit, and that draws upon the map the polygon separation link and the road separation link which are separated by the separation unit.