Gravitational comparison between a point mass and prism mass model

Gravitational quantities of a prism and a point mass are being derived for specified heights.

Two mass models and their gravitational quantities, gravitational potential,
gravitational attraction and the gravity gradients are being compared. Basis are the formulas of Heck and Seitz 2006 which were also used for the tesseroids-1.0 software of Leonardo Uieda 2011. The Code derives the quantities at ground and at a height of 255km. At this height there is almost no difference between both models because the Prism mass model acts as a point mass model. Only at ground both model show differences.