Alidade

image of alidade

Alidade

The alidade (left) consists of a telescope attached to a level plane and was a key tool used in topographic surveying.  The telescope can determine vertical angles and therefore changes in elevation or land surface between points. In the field, the alidade would be mounted to a drafting table on a tripod set at an optimal height for topographers to create topographic maps in the field while surveying.

Surveying
Alidade