Sets the selected hard ground regions passive. Passive hard ground regions are not included in noise calculations.
Find it here:
MOUS_ICO Menu: Noise > Hard ground regions > Passive
MOUS_ICO Menu: Noise > Hard ground regions > Dialog box
MOUS_ICO Select one or several hard ground regions in the list
MOUS_ICO Dialog box: Passive
nco: Select a hard ground region
MOUS_ICO Popup menu: Passive