Patent ID: 8392475

Claim:
A computer-implemented method of making a safe relief of a terrain for enabling an aircraft to fly safely at a low altitude above the terrain, the method comprising: obtaining an unsafe relief of said terrain, wherein said unsafe relief relates to a surface which represents a ground of the terrain, and obtaining a position of a high point representing a top of an obstacle extending upright from the terrain into the low altitude above the terrain, by making use of a primary database of said terrain containing information representing said unsafe relief and said obstacle; and combining with said unsafe relief a main volume that is defined between (i) a main volume base on the unsafe relief and (ii) an envelope, so as to obtain the safe relief of said terrain for overflying that contains at least said unsafe relief and said main volume, said main volume base having an area defined by a closed peripheral curve on said unsafe relief, the closed peripheral curve extending on said unsafe relief around an axis extending in a gravity direction through said high point and said unsafe relief, said envelope being generated using a segment of predetermined length extending from said high point to a second point that is on said closed peripheral curve and is moved along the entirety of said closed peripheral curve; wherein at least two high points overlie said terrain, a link line connects together said two high points, the link line having a predetermined thickness and a link length shorter than said predetermined length; the method further including adding a secondary volume to said unsafe relief, the secondary volume lying between said link line and an orthogonal projection of said link line onto said unsafe relief in order to optimize said safe relief.