According to RTU Syllabus

SURVEYING

LINEAR AND ANGULAR MEASUREMENTS

Part-4

Mistakes & Errors

Mistakes-

They are caused by carelessness or poor judgement.

ex-

• A reading of 10m is booked as 1m.
• Miscounting the no.of tape lengths. etc.

These can be revealed by taking the same measurement again with the same instrument.

Errors

• It does not arise due to mistake.

Errors are classified as-

1. Systematic error/Cumulative error
2. Random error/Accidental error/compensating error

Error = Measured value - True value

Correction = True value - Measured value

Systematic Error/Cumulative Error

• These Errors follow a definite mathematical or physical law.
• They are cumulative in nature.

          e.g.-

          Expansion of steel tape due to increase in temperature.

• These Errors can be checked by remeasuring the quantity by a different method using different instrument.

Random Error/Compensating Error/Accidental Error

• These are the Errors which remains after the mistakes and systematic errors are removed.
• They are random in nature.
• They are mainly caused by limitations of observer and instruments.

Aditi Sharma

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