A navigation system, comprising - an input device for inputting an input scale value (EM, EMN), - a display device for displaying road map information according to a selected display scale value (GA, GAMN) and - a processor device which is configured and is coupled to the input device and to the display device such that - the number of input scale values which can be input is greater than the number of display scale values which can be selected, and - such that the display scale value (GAMN) can be determined according to the following steps: - setting the input scale value as the display scale value (GAMN) when the input scale value is equal to a selectable display scale value, - determining a display scale value closest to the input scale value when the input scale value is not equal to a selectable display scale value, - setting the determined display scale value as the display scale value (GAMN) when the determined display scale value is not equal to the last selected display scale value, - setting the next-greater display scale value (NAM+) to the determined display scale value as the display scale value (GAMN) when the determined display scale value is equal to the last selected display scale value and when the input scale value is greater than the last selected display scale value, and - setting the next-smaller selectable display scale value (NAM-) to the determined display scale value as the display scale value (GAMN) when the determined display scale value is equal to the last selected display scale value and when the input scale value is smaller than the currently selected display scale value. - an input device for inputting an input scale value (EM, EMN), - a display device for displaying road map information according to a selected display scale value (GA, GAMN) and - a processor device which is configured and is coupled to the input device and to the display device such that - the number of input scale values which can be input is greater than the number of display scale values which can be selected, and - such that the display scale value (GAMN) can be determined according to the following steps: - setting the input scale value as the display scale value (GAMN) when the input scale value is equal to a selectable display scale value, - determining a display scale value closest to the input scale value when the input scale value is not equal to a selectable display scale value, - setting the determined display scale value as the display scale value (GAMN) when the determined display scale value is not equal to the last selected display scale value, - setting the next-greater display scale value (NAM+) to the determined display scale value as the display scale value (GAMN) when the determined display scale value is equal to the last selected display scale value and when the input scale value is greater than the last selected display scale value, and - setting the next-smaller selectable display scale value (NAM-) to the determined display scale value as the display scale value (GAMN) when the determined display scale value is equal to the last selected display scale value and when the input scale value is smaller than the currently selected display scale value.