Basic concepts 
 of surveying 
 and survey 
 instrument: 
 Dumpy Level
   Basic concepts of surveying and survey instrument: 
   Dumpy Level
   • Definition and terms used in levelling.
   • Principles of levelling.
   • Reduction of levels by Collimation method and Rise and Fall method.
   • Levelling difficulties.
   • Knowledge about the instrument: Dumpy Level.
   • Purpose of levelling.
   • Classification of levelling.
   • Curvature and Refraction.
   Basic concepts of surveying and survey instrument: 
   Dumpy Level
   • Definition and terms used in levelling.
   • Principles of levelling.
   • Reduction of levels by Collimation method and Rise and Fall method.
   • Levelling difficulties.
   • Knowledge about the instrument: Dumpy Level.
   • Purpose of levelling.
   • Classification of levelling.
   • Curvature and Refraction.
                Levelling                               Principle of Levelling
   An art of determining the relative            The principle      of   levelling  lies   in
   height of different points on, above          furnishing a horizontal line of sight and
   or belowthesurface.                           finding the vertical distances of points
   Levelling is of prime importance to           above or below the line of sight.
   an engineer for the purpose of                The line of sight is provided with a level
   planning, designing and executing             and a graduated levelling staff is used
   the                                           for measuring the height of the line of
   various engineering projects such as          sight above the staff positions.
                                                 .
   roads, railways, canals, dams, water
   supplyandsanitaryschemesetc.
   The success of any engineering
   project is based upon the accurate
   and complete levelling work of the
   project.