This paper contains methods of gravity and magnetic data processing with evaluation of effective density and magnetic intensity of rocks. The most preferred method of 3D-processing so as to create three dimensional models of gravity and magnetic distribution is that one which count gravity and magnetic fields around a circle near the calculation point. It is highly effectively to use this method if there are some isometric objects. This algorithm leads to a geometry distortion of the resulting objects and a marked increase in predicted depth if examined bodies are twodimensional and overlie horizontal or aslope. This might cause errors in data interpretation.
