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The possibility of modeling gravity field of the Earth along the leveling lines using the gravity observations at the leveling benchmarks has been studied. As the case study, gravity observations along the first order-leveling network of Iran has been considered. The mathematical models that have been developed for this purpose are
polynomials of degree 4 and degree 8. The efficiency of the aforementioned models has been compared with the ellipsoidal harmonic expansion to degree and order 20, 180, 360 and the Somigliana-Pizzeti gravity field. The test computations have proven that a polynomial model of degree 4 can be considered as the best choice for the gravity field modeling along the leveling lines. Based on the case study of gravity field modeling along the leveling lines of Iran, the polynomial model of degree 4 can provide 20 mGal accuracy which is quite enough to provide the accuracy level of the gravity data needed for the precise leveling based on the current demands. Therefore, by applying such a model the need for the gravity observations along the leveling lines will be reduced and as such great reduction in the expense of the precise leveling observations will be achieved