Area navigation system including a map display unit for establishing and modifying navigation routes

摘要

An area navigation system including a map display unit for entering navigation information to form or modify a programmed navigational route is disclosed. The map display unit is connected to an area navigation computer to supply a cartographic display of a geographic area relevant to a particular navigation route. Specific geographic locations to be used as reference points, or to be eliminated from a previously programmed navigation route, are selected by means of a cursor symbol that is electronically generated on the cartographic display. The position of the cursor symbol and the geographic region displayed are controlled by a single switch located on a control apparatus. When a desired geographic reference point is selected by means of the switch and cursor symbol, operation of an approproate control either enters the coordinates of the selected geographic location into the area navigation computer for use as a new navigational reference point, or deletes the selected geographic location from a previously computed navigation route. The navigation route established by operation of the map display unit and the associated controls is temporarily stored in a provisional storage buffer and is displayed on the map display unit cartographic display. Accordingly, a complete navigational route or a complex modification of a previously established navigational route can be observed and verified prior to the initiation of output signals from the area navigation system.