The purpose of this study is to evaluate the effectiveness of residual terrain model (RTM) correction in the gravity anomaly interpolation. To evaluate, after removing the long wavelength gravity anomaly by the global Earth Gravitational Model and correcting RTM to gravity anomaly data, the interpolation is performed using the Collocation method according to 2 options: (1) with RTM correction and (2) without RTM correction. The interpolated result is compared with known values to assess accuracy. The experiment was conducted in the Central Region of Vietnam with 9871 calculated points and 1060 test points. The experimental results show that: After RTM correcting, the gravity anomaly model is smoother and less variable; The accuracy of gravity anomaly interpolation increases; The Root Mean Square deviation (RMS) decreases by 1.306 mGal, from 4.559 mGal to 3.252 mGal. Thus, RTM correcting before interpolating gravity anomalies is necessary and effective.
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