Errors in Surveying

ERRORS IN SURVEYING

Definition: The discrepancies between observed and true value of any measured quantity is known as errors in surveying.

Source of error:

Source

1. Instrumental
2. Natural
3. Personal

Types of errors in surveying:

Types

1. Compensating error
2. Cumulating error
3. Mistakes
4. Accidental error

Causes of Error:
1. Compensating error:

• Incorrect holding of chain
• Horizontal and vertically  of steps not being properly  maintained during the stepping operation.
• Fractional parts of the chain or tape  not being uniform through in length
• Inaccurate measurement of right angles with chain and tape.

2. Cumulative error:

• Contraction of chain or tape
• Slop correction not applied
• Sag correction not applied
• Measured with faulty alignment
• Measurement taken in high wind

Negative error:

• The opening of ring joints
• Applied pull is greater than standard pull
• Temperature is being high
• Wearing of connecting rings
• Elongation of  the links

Mistakes:

• Erroneous recording such as 945 in place 954
• The counting of 8 for 3
• Forgetting once chain length
• Making mistakes in using a calculator

Accidental error: 

• Its can occur  due to unavoidable circumstance like variation  in atmospheric condition which  are entirely beyond the control of the observer.