The invention relates to the field of methods for zooming onto a part of an image which consists of pixels and which represents a terrain overflown by an aircraft. It is a zoom method for zooming onto a part of an image which consists of pixels and which represents a terrain overflown by an aircraft, an image being modulated, pixel by pixel, by a shading cue representative of the relief of a terrain. The shading cue is determined by way of a computation carried out, in a reference frame of a display screen of an aircraft, pixel by pixel, on the basis of the altitudes of pixels neighboring the current pixel in the case of the unzoomed image. The method according to the invention can in particular be implemented in a cartographic accelerator card.