Method for automatically adapting the range of visibility in a three-dimensional synthetic representation of the outside landscape in an on-board display system for aircraft

A method for three-dimensional graphic representation of the outside landscape in an on-board display system for aircraft comprises a graphical computer and a display screen. The graphic representation is computed to a visibility distance. In the method the zero pitch line of the aircraft forms, with the real horizon line, a first angle, the line representing the limit of the visibility distance forming, with the real horizon line, a second angle, in a first step, the graphical computer determines the maximum visibility distance such that the difference between the first angle and the second angle remains less than a determined value; in a second step, the graphical computer determines the visibility distance as a function of the maximum visibility distance, of the maximum altitude of the relief of the local environment and of the flight phase.