Airport feature data interchange method for conformal display

An airport feature data interchange method provides bandwidth reduction in airport feature data interchange in an aircraft by: obtaining (61) the absolute coordinates of an airport reference location (e.g. an airport monument); obtaining (62) the absolute coordinates of an airport feature (e.g. a runway, a taxiway etc.); communicating said absolute reference location coordinates to a display device (12,14,15); computing (63,64,65,66,67) relative airport feature coordinates of said airport feature relative to said airport reference location; and communicating (68) said relative airport feature coordinates to said display device (12,14,15).