Patent ID: 7634335

Claim:
A method of estimating distances of points in a map extracted from a terrain elevation database, with respect to an aircraft subjected, to dynamic altitude restrictions prohibiting it from crossing certain reliefs on the map that are too high whose configuration varies according to the vertical flight profile imposed upon it and, to constraints and restrictions coming from air navigation regulations; the terrain elevation database having a set of points each referenced by an elevation, a latitude and a longitude, and corresponding to the regular meshing of a location grid; the methods comprising the steps of implementing, on the image constituted by the elements of the database which correspond to the map and are disposed in lines and columns in order of values of latitude and longitude, a propagation distance transform assimilating the distances of the different points of the image with respect to a source point placed close to the aircraft, to the shortest joining paths compatible with the dynamic altitude restrictions of the aircraft and with air navigation constraints and restrictions.