Abstract: Radio system for video display of a map and symbols traced on the map: It comprises means for radio transmitting a plurality of digital messages, each including the address of a map among a plurality of maps, the definition of symbols among a plurality of symbols and the coordinates of the symbols on the map. At the receiving station, there is provided a display device having a plurality of points defined by coordinates and which can be selectively activated, a plurality of transparent views representing the maps and a selector for selecting a view of given address. The selected view is projected on to the display device. The message including a map address equal to the address of the selected view is also selected and display logic means activates the points of the display device in response to the definition and coordinates of the symbols contained in the selected message.

Abstract: A video system for assisting automobile traffic is provided. Radio frequency signals concerning traffic flow and build-up are transmitted to a receiver unit contained within a motor vehicle. The receiver unit contains road map information stored in a memory and only information relating to traffic flow is transmitted. The receiver superimposes the traffic flow information with the map information to produce a composite image of traffic conditions. The traffic flow informationis updated and stored in a memory while obsolete information is blanked out so that current traffic information may be presented to the viewed.