The Planetable: Instruments and Methods for Topographic Surveys and Construction Layout

Abstract

The planetable alidade is an articulated hybrid surveying and drafting instrument system that enables a topographer to simply and directly communicate with the map sheet which, in a very real sense, is an extension of the topographer’s perception of a landscape. The instrument is capable of performing all the usual survey functions with the exception of field astronomy. It is also unsurpassed as a basic instrument for teaching fundamental concepts of surveying because the geometric principles are readily grasped, and the objective of a survey operation is clearly indicated on the map sheet.