to determine the curvature of a median direction 46 of the structure 40 from the inclinations measured by each of the objects 42 and 44 to simplify illustration the data bus and the computation unit are not illustrated in fig5 the inclination of these objects 42 and 44 is defined relative to the direction of the gravity field g which in this case is vertical this computation unit is notably programmed to evaluate the inclination at any point of the structure 40 from the measurements supplied by the objects 42 and 44 for example by means of interpolation methods such as cubic spline interpolation and to compute from the knowledge of this inclination at any point of the structure 40 the curvature k at any point of the direction 46 of the structure 40 for example by means of the following formula assuming that the median direction of the structure is not left in which k s is the curvature of the direction 46 at the point s of curvilinear abscissa s the origin of the curvilinear abscissa being set arbitrarily and d s being the inclination of the structure 40 at the point s of curvilinear abscissa s these examples of interpolation and reconstruction methods are for example described in chapter 1 of the doctoral thesis by n sprynski u201c reconstruction of curves and surfaces from tangential data u201d joseph fourier university.