Topography indicator for aircraft

Claim 1

IN AN AIRCRAFT TOPOGRAPHY INDICATOR CONTROLLABLE BY A NAVIGATION COMPUTER YIELDING FLIGHT DATA OF THE SPEED, DIRECTION AND DRIFT TYPE FOR CONTINUOUS INDICATION OF THE POSITION OF AN AIRCRAFT BY THE PROJECTION ONTO A SCREEN OF A MAP OF THE AREA OVER WHICH THE SAID AIRCRAFT IS FLYING, THE AIRCRAFT BEING REPRESENTED BY A SYMBOL PROJECTED ONTO THE SAME SCREEN OVER WHICH THE IMAGE OF THE MAP PASSES, THE SAID MAP BEING MOVABLE, ASSOCIATED WITH IDENTIFICATION MEANS, AND HAVING ITS MOVEMENTS CONTROLLED BY THE SAID NAVIGATION COMPUTER, COMPRISING: PROJECTION MEANS CONSISTING OF AT LEAST ONE LIGHT SOURCE, AN OPTICAL SYSTEM AND A PROJECTION SCREEN, THE SYMBOL DENOTING THE AIRCRAFT BEING DISPOSED IN AN OBJECT PLANE OF THE OPTICAL SYSTEM SO AS TO BE PROJECTED ON THE SAID SCREEN; A MAGAZINE TO CONTAIN DETACHABLE INDIVIDUAL MAPS OF THE AREA OVER WHICH THE AIRCRAFT IS TO FLY, THE MAPS TOGETHER FORMING A GRID; CARRIER MEANS WHOSE ORTHOGONAL MOVEMENTS ARE CONTROLLED FROM THE NAVIGATION COMPUTER TO MOVE THE MAP IN ITS OBJECT PLANE DURING ITS PROJECTION; SELECTION MEANS WHEREBY A MAP CORRESPONDING TO THE AREA OVER WHICH THE AIRCRAFT IS NEXT TO FLY IS SELECTED FROM THE INDIVIDUAL MAPS IN SAID MAGAZINE IN DEPENDENCE ON THE POSITION OF THE MAP STILL BEING PROJECTED ONTO THE SCREEN AND THE POSITION OCCUPIED BY THE NEXT MAP IN THE GRID; AND TRANSFER MEANS CONTROLLED BY THE SAID SELECTION MEANS FOR INDIVIDUALLY BRINGING EACH OF THE INDIVIDUAL SELECTED MAPS INTO AN OBJECT PLANE OF THE OPTICAL SYSTEM FOR PROJECTION ON TO THE SAID SCREEN AND FOR RETURN TO THE SAID MAGAZINE; SAID INDIVIDUAL MAP MAGAZINE BEING MOABLE WITH RESPECT TO THE OBJECT PLANE PROVIDED FOR