Currently available model of the geoid on Poland’s territory enable to compute normal heights on the basic of accurate ellipsoidal heights, with an average accuracy of the ± 2 cm. Only some chosen parts of Poland have been verified to now. In this paper, a method of correcting of the model for a small region (about city Olsztyn) to sub-centimeter accuracy is given. Additional – but important product – effect of the method are accurate ellipsoidal heights of all the bench–marks located at the region of interest. However the corrected model of geoid is virtual, but it given correct results for the precise leveling network points. The limit of the methods is small size of the region where the model is suitable – in the exemple it is area of about 30 x 40 km.

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