The first known instrument for directly producing a drawing of a site was developed by Johann Richter, also known as Johannes Praetorius, a Nuremberg mathematician, in 1610. This circular table, called a tabula praetoriana, mensula praetoriana or Pretorian table, used a simple alidade and allowed a piece of paper to be slipped under the alidade for drawing.
Later devices adopted a rectangular table and enhanced the type and features of the alidade.
By using the alidade as a surveying level, information on the topography of the site can be directly recorded on the drawing as elevations. Distances to the objects can be measured directly or by the use of stadia marks in the telescope of the alidade.
NSPS opens 2005 Annual Student Competition.(The Latest News)(National Society of Professional Surveyors)(Brief Article)
Dec 01, 2004; The National Society of Professional Surveyors (NSPS) released the guidelines for its 2005 Student Competition. The competition...