Government Engineering College, Bhavnagar Civil Engineering Third Sem Government Engineering College, Bhavnagar Civil Engineering Third Sem. Subject : Surveying Topic : Theodolite Traversing Group No : 05 Name: Enrollment No.: Gamit Tarun T. Patel Yash H. Seta Nayan D. Bariya Raunak J. 130210106016 130210106042 130210106048 130210106005

Contents Theodolite Traversing Different methods of Traversing Closing Errors Computation of latitude and departure Check in closed or open traverse Balancing of Traverse

Theodolite Traversing A traverse is a series of connected lines whose lengths and directions are measured in the field. The system of surveying in which the angles are measured with the help of a theodolite, is called Theodolite surveying

Different methods of Traversing Fast angle method Loose needle method Included angle method Direct angle method Deflection angle method

1. Fast angle method In this method, the magnetic meridian is established only at the starting station. This method is used to measure the magnetic bearings and lengths of traverse legs

2. Loose Needle method In the loose needle method, the direction of the magnetic meridian is established at each traverse station and the direction of the line is determined with reference to the magnetic meridian. In this method the linear measurements are done with the help of chain or tape. It is also known as “ Free Needle Method “

3. Included angle Method This method is more accurate than the fast needle method. Traversing by the method of included angles is the most commonly used method. In this method, the magnetic bearing of any one line is measured in the field.

4. Direct angle method This method is similar to the method of included angles explained in the precending section. However, in this method, direct angles or the angles to the right are measured. This method is generally used in open traverse.

5. Deflection angle method This method is suitable for open traverse and is mostly employed in the survey of rivers, coast line, roads, railways, canals, etc.

Closing Errors If the condition of a closed traverse are not satisfied, there is an error of closer. The distance by which a traverse fails to close is known as ‘Closing error’ or ‘ Error of closure’.

Computation of latitude and departure 1. Latitude:- The Latitude of a line is its orthographic projection on the N-S axis representing the meridian. 2. Departure:- The departure of a line its orthograohic projection on the axis perpendicular to the meridian.

Check in closed or open traverse 1. Check in closed traverse Error in linear measurement For important work the most satisfactory method of cheking the linear measurement consists in chaining of each line should be done twice, along opposite directions.

 

2. Checks in an open traverse Tie line or cut-off line Auxiliary point

Balancing of Traverse A traverse is balanced by applying corrections to latitudes and departures. This is called balancing a traverse. In case of closed traverse, the algebraic sum of latitudes and departures must be equal to zero. The following are common methods of adjusting a traverse:- 1. Bowditch’s Rule 2. Transit Rule 3. Third Rule 4. Graphical Construction Method

1. Bowditch’s Rule  

2. Transit Rule  

3. Third Rule  

4. Graphical construction Method

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