The general field of the invention is that of methods for three-dimensional conformal representation of a terrain. The method is used in a piloting and navigation assistance system of an aircraft. The assistance system comprises a navigation system, a cartographic database, electronic calculation means a meteorological database and a display system allowing the superimposition of synthetic images on the exterior. The method comprises the following steps: Step 1: Calculation, for a determined position of the vehicle, of the terrain perceptible through the display system; Step 2: Selection of a part of the said terrain as a function of a distance or of an altitude or of a range of altitudes; Step 3: Calculation of a three-dimensional conformal cartographic representation of the said selected part of the terrain; and Step 4: Display of the said cartographic representation by the display system.