1. A non-transitory, computer-readable storage medium, having computer program instructions, which when executed by a processor perform a method for generating a map using geographic data of a geographic region that are stored together as map units, wherein the map units are hierarchically structured, map units of an n th order respectively correspond to a geographic partial region, n being a natural number, and map units of an (n+1) th order respectively correspond to a geographic subregion of one of the partial regions, the method comprising: determining boundaries of the geographic region using map units of a first order; querying map units of a map-unit database to select map units of at least one second order by reading identifiers that indicate that the selected map units contain a specified geographic data type, the at least one second order being higher than the first order, the selected map units being within the boundaries of the geographic region; reading the selected map units of the at least one second order having the specific geographic data type from the map-unit database; and displaying a map image by simultaneously displaying data of the map units of the first order and the selected map units of the at least one second order; wherein the displayed data of the map units of both the first and selected at least one second order include symbolic representations of the geographic data.