Abstract: A method of filing geographical maps and a method of reading the filed ma The maps cover a zone called scale zone. For filing, the maps are arranged in order, each map is turned through a digitization angle, it is digitized by a scanner and the useless portions are cut out therefrom, the maps are located so as to determine the deformation thereof, the digitized, cut out and located maps are stored on a buffer by juxtaposing them, and the information of the buffer is stored on a digital optical disk. For reading, the map containing a point with given geographical coordinates to be placed in the center of a display screen is determined by its contour.

Abstract: A method is provided for representing, on a display device screen and in perspective from a given point of observation, the image of a terrain known by the nodes of a given mesh network, in which for each image pixel, the point of intersection is determined of the line which starts from the point of observation and which passes through this image pixel with a surface passing through the nodes and taking on approximately the shape of the ground, and said image pixel is illuminated with the color of the pixel associated with a digitized planimetric map or photograph of the ground.

Abstract: A printing device, for example of the needle impact type, is equipped with lectrical means controlling the operation of the needles to produce alternative forms of printed data, for example letters of different degrees of inclination.

Abstract: The transducer device for reading or writing information on a magnetic surt comprises an insulating plate on one surface of which is deposited in thin layer form a magnetic circuit having an air gap and a conducting metal forming a turn. The turn is short circuited and the transducer device comprises a discrete magnetic circuit whereon is wound a winding and the turn is a primary or secondary winding of the circuit. It can be used as a reading or writing head for a magnetic disc.