In one dimension the direction is indicated by the sign: negative if to the left and positive if to the right. The word distance means how far the object moves regardless of direction. It is always positive and is equal to the absolute value, or magnitude, of the displacement.
Also, what do you mean by a positive displacement?
A positive displacement pump makes a fluid move by trapping a fixed amount and forcing (displacing) that trapped volume into the discharge pipe. Some positive displacement pumps use an expanding cavity on the suction side and a decreasing cavity on the discharge side.
What is a positive displacement machine?
The machines whose functioning depend mainly on the change of volume of a certain amount of fluid within the machine are known as positive displacement machines. The word 'positive displacement' implies that there is a physical displacement of the boundary of a certain mass of fluid.