Abstract: A method for operating a navigational system having a digital map base which is a reproduction of real geographical regions and contains data on geographical elements, as well as a device which retrieves and processes data, such as an operating device having a display unit. In this context, a data directory of the data present in the digital map base is transmitted to the device which retrieves and processes data, and the device which retrieves and processes data selects data, to be requisitioned from the digital map base using this data directory.

Abstract: The invention relates to a method for operating a navigation system comprising a digital map base, which is a representation of actual geographical areas and which contains data of geographical elements. The navigation-system also comprises a unit, which retrieves and processes the data, such as an operating unit provided with a display device. The data in the digital map base is combined in the form of geographically defined page frames. When requesting a page frame from the digital map base, data of geographical elements which extend beyond the edge of the page frame is transferred in such a manner that data pertaining to these geographical elements located outside of the requested page frame is also compiled and transferred.

Abstract: A method, operating unit, navigation system and interface for displaying a predetermined section of a digital map database, which represents a real geographic area, on a display device are described. The digital map database contains data representing various geographic elements. An attribute, which defines a display priority, is assigned to each geographic element. An evaluation is then performed to determine whether or not particular geographic elements in the predetermined section to be displayed should or should not be visible on the display device. A particular geographic element is made visible on the display device when it is located in the predetermined section and when its display-priority-determining attribute satisfies certain selection criteria or selection rules. This method prevents display of too many geographic elements, which would otherwise make the display congested thus producing an unclear display.

Abstract: A method, operating unit, navigation system and interface for displaying a predetermined section of a digital map database, which represents a real geographic area, on a display device are described. The digital map database contains data representing various geographic elements. An attribute, which defines a display priority, is assigned to each geographic element. An evaluation is then performed to determine whether or not particular geographic elements in the predetermined section to be displayed should or should not be visible on the display device. A particular geographic element is made visible on the display device when it is located in the predetermined section and when its display-priority-determining attribute satisfies certain selection criteria or selection rules. This method prevents display of too many geographic elements, which would otherwise make the display congested thus producing an unclear display.