An aerospace technician is testing a high-power solenoid valve designed for a satellite propulsion system. To ensure the leakage magnetic field does not interfere with the satellite's sensitive navigation instruments, the technician must map the shape and direction of the magnetic field lines around the active solenoid.

Describe a step-by-step practical procedure the technician could use, with the aid of a plotting compass, to map the shape and direction of the magnetic field lines on a sheet of card.