Telescopic Alidade
telescopic alidade
[¦tel·ə¦skäp·ik ′al·ə‚dād]Telescopic Alidade
an instrument used in topographic surveying, along with a topographic drawing board, for plotting relief, contours, and ground features on a map. The alidade consists of a rule for drawing straight lines on the drawing board and an upright that supports on the horizontal axis a telescope with stadia hairs and a vertical circle with degree readings for determining angles of slope.