Comparative assessment of linear and bilinear prism-based strategies for terrain correction computations

We address the evaluation of the potential and of the gravitational attraction of mass distributions, assigned by means of a Digital Terrain Model (DTM), for terrain correction computations. In particular, we improve a recent analytical formulation based on the approximation of topographic masses by vertical prisms with linear top surfaces and compare the computational features of the enhanced formulation with alternative ones based on polyhedral modeling, on bilinear approximation of the surface relief or on numerical approaches. The numerical tests carried out on the DTM of an area near Cassino (Italy) proved that the proposed enhanced analytical formulation, besides providing exact values of the potential and of the gravitational attraction, turns out to be faster than alternative approaches.