Chapter:

levelling-lab-sheet

1. DETERMINATION OF ELEVATION OF VARIOUS POINTS WITH LEVEL MACHINE

TITLE:

DETERMINATION OF ELEVATION OF VARIOUS POINTS WITH LEVEL MACHINE

OBJECTIVES:

  • To find the R.L of various station of a traverse.

THEORY:

The art of determining and representing the relative height or elevation

of different object/points on the surface of earth is called leveling. It deals with the measurement in vertical plane. 

By leveling operation, the relative position of two points is known whether the points are near or far off. Similarly, the point at different elevation with respect to a given datum can be established by leveling. 

The levelling operation generally includes following process:

  • Temporary adjustment

  • Permanent adjustment

The levelling operation generally includes following process:

  • Setting up level

  • Fixing the instrument in tripod

  • Approximate levelling by leg adjustment

  • Levelling up with the help of foot screws

  • Elimination of the parallax

 The system of working out the reduced level of the points from staff reading taken in the field is called as reduced level (R.L) of a point.There are two systems of reduced levels:

  • H.I Method

  • Rise and fall Method

APPARATUS REQUIRED: 

  1. Level Machine

  2. Staff

OBSERVATION AND CALCULATIONS:

CHECKS:

RESULTS:

Thus, the reduced level of various stations were determined.

SOURCES OF ERROR:

  • Error due to imperfect adjustment

  • Error due to sluggish bubble

  • Error due to natural sources like earth curvature, refraction etc.

  • Error due to mistakes in recording, sighting, manipulation etc.

CONCLUSIONS:

Thus, the reduced level of various stations were determined, which can be utilised for further operation in contouring.

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