In one embodiment, a medical probe tracking system includes a first probe, a magnetic field generator to generate a magnetic field, and processing circuitry to measure first electrical currents between body surface electrodes and first probe electrodes, receive magnetic position signals from a magnetic field sensor of a second probe, compute first position coordinates of the first probe in a first coordinate frame responsively to distribution of the first electrical currents, render an initial 3D representation of the first probe in the first coordinate frame and then compute a current-position map with respect to a second coordinate frame defined by the magnetic field generator, find a transformation between the first and second coordinate frames, apply the transformation to the first position coordinates yielding second position coordinates, and render a modified 3D representation of the first probe according to the second position coordinates in the second coordinate frame.