R.T.U / G.I.T Jaipur                         SUBJECT –Surveying (3CE4-05)     CIVIL ENGG./ III SEM
                                              UNIT –2 
                                            Levelling 
    1                                                                             PRATEEK SHARMA
  R.T.U / G.I.T Jaipur                         SUBJECT –Surveying (3CE4-05)     CIVIL ENGG./ III SEM
       •   Blown up Detail:-
       1.1 Definition of Levelling 
       1.2 Levelling Terms 
       1.3 Types of levelling
       1.4 Reduced Level Calculation  
       1.5 Curvature correction(Cc) 
       1.6 Distance of visible horizon 
       1.7  Levelling Instrument 
       1.8 Errors in Levelling 
       1.9 Contours and contour lines
       1.10 Methods of Contouring
       1.11 Area and volume measurements
    2                                                                             PRATEEK SHARMA
  R.T.U / G.I.T Jaipur                                   Surveying  (3CE4-05)             CIVIL ENGG./ III  SEM
     1.1 Definition of Levelling              
     •    Levelling or leveling is a branch of surveying, the object of which is to establish or
          verify or measure the height of specified points relative to a datum.
     •    It is widely used in cartography to measure geodetic height, and in construction
          to measure height differences of construction artifacts.
     •    Leveling is the general term applied to any of the various processes by which
          elevations of points or differences in elevation aredetermined.
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  R.T.U / G.I.T Jaipur                                   Surveying  (3CE4-05)             CIVIL ENGG./ III  SEM
     1.2   Levelling Terms    
           Basicterms:
     •    Vertical line- A line that follows the local direction of gravity as indicatedby 
                          a plumbline.
     •    Level surface - A curved surface that, at every point is perpendicular tothe  local 
          plumb line (the direction in which gravityacts).
     •    Level line - A line lying in a level surface is a level line. It is thus a curved line normal 
          to the plumb at all points.  In field surveying, it is defined by the direction of a freely 
          suspended plumb-bob.
     •    Horizontal plane - A plane perpendicular to the local direction of gravity.In  plane 
          surveying, it is a plane perpendicular to the local verticalline.
     •    Horizontal line - A line in a horizontal plane. In plane surveying, it is aline
     •    perpendicular to the localvertical.
     •    Vertical datum - Any level surface to which elevations are referenced. Thisis  the 
          surface that is arbitrarily assigned an elevation ofzero.
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