Error and Accuracy in Survey-Types of Error

Error and accuracy in survey is one of the most important terms in surveying.Accuracy is the degree of perfection obtained.But precision is the degree of perfection used in the instruments.

error and accuracy in survey

Accuracy depends upon

  1 Precise instruments

  2 Precise methods

  3 Good planning

Error and Accuracy in survey

Source of errors

Instrumental error

Error may arise due to faulty adjustment and imperfection of the instrument with which measurement is being taken.If the tape used in the operation is too long

Personal error

Error may arising due to the human.It is caused due to careless during taking observation

Natural error

Error may be arising due to the natural phenomenon such as temperature ,humidity ,gravity,wind,refraction and declination

Kinds of error

Mistakes

Mistakes are errors which arising from inattention,inexperience,carelessness and poor judgement or confusion in the mind of observer

Accidental errors

Accidental error are those which remain after mistakes and systematic errors have been eliminated and are caused by a combination of reasons beyond the ability of the observer to control.

Compensating error 

This type of errors occures in both direction,that is both positive and negative.Therefore the resultant will be compensating.They are automatically cancelled.Some examples are

  1. Inaccurate bisection
  2. Inaccurate centering
  3. Careless in marking chain lengths

Systematic errors

A systematic error may always be same under same codition and it will have same size and sign.For example, in the case of a tape.If the tape of length x short is streched to N time then the total error in the tape will be N times x

The reason for the systematic error is

  1. Variation of temperature
  2. Variation of humidity
  3. Variation of pressure

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