1. A method, by a position reporting node in a communication network, for reporting positioning data in the communication network, comprising: obtaining positioning data comprising a definition of a polygon in a lateral plane with altitude information for each corner of the polygon and a confidence value; approximating said polygon with an ellipsoid point that has an altitude, wherein said approximating comprises calculating a lateral center of gravity of said polygon as lateral parameters of said ellipsoid point; and calculating a mean of said altitudes associated with said corners of the polygon as an altitude parameter of said ellipsoid point; further approximating said polygon with an uncertainty ellipsoid that surrounds said ellipsoid point, wherein said approximating comprises calculating an uncertainty ellipse around the ellipsoid point; transforming the uncertainty ellipse into a corresponding uncertainty ellipsoid, defined by semi-principal axes a, b, and c, by calculating a covariance in the vertical direction; obtaining a scaling factor corresponding to the confidence value based on a Gaussian assumption of the confidence value associated with the polygon with altitude; and scaling the three semi-principal axes a, b, and c of the uncertainty ellipsoid with the scaling factor; and reporting said lateral parameters and altitude parameter of said ellipsoid point, and reporting said scaled uncertainty ellipsoid, over an interface of said communication network, as a representation of said positioning data.