1. A method for determining and ordering the characteristic points of a bridge on an airport map, the said airport map comprising: a set of polygons characterizing elements of linkway type, each polygon exhibiting an identifier, and each polygon being defined by a set of points, each point common to two polygons having a single mathematical representation, bridge (B) defined by a set of at least four points comprising the following steps: the determination of a set of neighbouring polygons adjoining the said bridge from among the set of polygons, for each point of the bridge, the verification of its possible equality with a point of one of said neighbouring polygons, consequently called adjacent polygon, so as to construct a set of 2 to N common points, N being greater than or equal to 4, the recording, for each common point, of the identity of the polygon or polygons to which it belongs, the determination of four characteristic points of the bridge, notably from among the common points found in step 2, the determination of the two pairs of characteristic points, corresponding to a step of ordering the said characteristic points, said pairs constituting segments approximately parallel to the direction of travel over the bridge.