1. Method for automatically determining the contours of heights of the relief, such as hillocks and hills, of a geographical area (ZO), in particular terrestrial or submarine, according to which method the following successive operations are performed automatically: a) on the basis of an image of said geographical area (ZO), which contains altimetric data of points therein, the background surface of the relief which illustrates the gradual variations in the altitudes of said geographical area (ZO) is eliminated, by implementing what is known as a top hat algorithm, which uses a structuring element ( 28 ) which is adjustable; b) on the basis of the results of step a), thresholding is performed to form a binary image (IB) of the relief seen from above, containing only reliefs having heights above a threshold value which is adjustable; c) from this binary image (IB) which comprises two different types (Z 1 , Z 2 ) of area, rough contours of the heights of the relief are extracted, illustrating the boundaries between these two different types (Z 1 , Z 2 ) of area; and d) said rough contours are simplified so as to obtain a set of polygons (P 1 , P 2 , P 3 ) illustrating the contours (C 1 , C 2 , C 3 ) of the heights of the relief of said geographical area (ZO).