Abstract: Drafting apparatus comprises a drafting head having X and Y scribing edges. The drafting head is mounted for movement along a beam in the Y direction and its position is detected by an encoder. The beam is mounted for movement in the Y direction relative to the drawing surface and its position is detected by another encoder. The encoders control a numerical display device indicating instantaneous X and Y displacements of the scribing edges from a datum set by a zeroing control. A scaling device is arranged operatively between the encoders and the numerical display device whereby the numerical display device will indicate the real values represented by proportional X and Y displacements. The drafting head is rotatably mounted from a carriage and a third encoder detects the angular position of the drafting head and controls the numerical display device to indicate the instantaneous angular position of the drafting head.