In distance maps used in order to facilitate the navigation of craft such as an aircraft, the distances estimated take into account obstacles to be circumvented but not the maneuverability of the craft. The adaptation route required by the craft in order to take the right direction is not taken into account so that certain distance estimates for accessible points located in the neighborhood of the craft are unrealistic. In order to make a distance map more realistic, it is proposed that an obstacle of concave shape associated with the craft be added behind the position of the craft, forcing the estimations of distances to be circumvented an area that is inaccessible to the craft for reasons of maneuverability.