How is the 0.9 m obstruction distance measured?

World Netball Rule 16. Obstruction is a penalty pass, taken where the infringer was standing (or where the obstructed player was, if that would disadvantage the non-infringing team).

A defender may try to intercept, deflect or defend the player with the ball if there's at least 0.9 m (3 ft) on the ground between the nearest part of the landing foot of the player with the ball and the nearest part of the defender's nearer foot.

Measuring:

• One-foot landing: from the landing foot; if it's lifted, from where it was grounded.
• Two-foot landing: if neither foot moves, from the closer foot; if one foot moves, from the foot still grounded.
• Pivoting: the measuring point moves with the landing foot, and the defender must readjust.
• Lifted defender: measured from either defender's nearer grounded foot.

Allowed:

• From the correct distance, jumping upwards or towards the player and landing inside 0.9 m, as long as it doesn't interfere with the pass or shot.
• Being closer because the player with the ball moved closer.
• Standing inside 0.9 m without making any attempt to defend (and without interfering with the pass or shot).

Players without the ball (16.8-16.9): within 0.9 m of an opponent, a player may stretch out their arms only to catch, deflect or intercept a pass or fake pass, to catch, deflect or bat a rebound, or to signal briefly. Arm movements away from the body that block an opponent's movement are obstruction, beyond natural body stance.