A microprocessor-based controller has been developed to reorient the magnetic field gradients used in nuclear magnetic resonance zeug-matographic imaging. The principle of operation is that linear field gradients correspond to vectors, and may be generated from their orthogonal components. Under microprocessor control, the currents in the gradient coils may be manipulated to produce programmed linear field gradients with any desired magnitude and orientation. The controller has been used in two-dimensional reconstruction experiments and for sensitive point scanning, and may readily be adapted to three-dimensional imaging and to other gradient sequences.