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Classification of Leveling

Simple Leveling 

It is the simplest operation in leveling when it is required to find the difference in elevation between two

 points, both of which are visible from a single position of the level.

 Differential Leveling 

It is the operation of leveling to determine the elevations of points some distance apart, or to establish

BMs. It is adopted in cases when 1) If the stations are too far apart 2) If the difference in elevations

 between them is too great or 3) If there are obstacles intervening.

In such a case, it is necessary to set up the level in several positions and to work in a series of stages, the

method of simple leveling is employed in each of the successive stages.

Check Leveling 

It is the operation of running the levels for the purpose of checking a series of levels, which have been

 previously fixed.

 Profile Leveling 

It is the operation in which the object is to determine the elevations of points at known distances apart

along a given line, it is adopted for projects such as Roadways/Highways, Tunnels, Sewerage pipes lines

and water works etc. The given line as mentioned above, in these types of projects is the centerline of the

roadway/highway, tunnel, pipeline etc.

Cross Sectioning 

It is the operation of leveling to determine the surface undulations, transverse to the given line and on

either side of it.

 Reciprocal Leveling 

It is the method of leveling in which the difference in elevation between two points is accurately

determined by two set of observations when it is not possible to set up the level midway between the two

 points.

 Barometric Leveling 

It is the method of leveling in which the altitudes of points are determined by a barometer, which actuallymeasures atmospheric pressure.

 Hypsometry

It is the method of leveling in which the heights of mountains are found by observing the temperature at

which water boils.

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Trignometrical Leveling 

It is the process in which the elevations of points are computed from the vertical angles and horizontal

distances measured in the field.

Reduction of Levels

There are two methods of working out the reduced levels of points from the staff readings taken in the

field.

1) The Collimation or Instrument Height Method

2) The Rise & Fall System

1) The Collimation or Instrument Height Method 

It consists in finding the elevation of the plane of collimation i.e. height of instrument for every setup of 

the instrument, and then obtaining the reduced levels of points with reference to the respective plane of 

collimation. The reduced levels of the successive points are found by subtracting their staff readings from

the elevation of this plane of collimation. This process is repeated until all the reduced levels are worked

out. On completing the reduction of the levels, the accuracy of the arithmetical work should be checked.

Arithmetical Check 

∑B.S - ∑F.S= R.L last – R.L first

2) The Rise & Fall System

It consists in determining the difference of level between consecutive points by comparing each point

after the first with that immediately preceding it. The