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instrument and personal vision of an individual. The following are the
examples:
1. Faulty alignment of a line.
2. An instrument is not leveled properly.

3. An instrument is not adjusted properly.
If undetected, systematic errors are very serious. Therefore, (1) all
surveying equipment must be designed and used so that, whenever

possible, systematic errors will be automatically eliminated, and (2)
all systematic errors that cannot be surely eliminated by this means
must be evaluated and their relationship to the conditions that cause
them must be determined.

Compensating Errors: This type or surveying error tends to
occur in both directions, i.e. the error may sometimes tend to be
positive and sometimes negative thereby compensating each other.

They tend sometimes in one direction and sometimes in the other, i.e.
they are equally likely to make the apparent result large or small. The
following are a few examples:

1. The discrepancy between chain and tape measurements when
both are used simultaneously.
2. Inaccuracy in marking chain lengths on the ground.

3. Inaccurate centering.
4. Inaccurate bisection of an object.
They obey the laws of chance and therefore must be handled
according to the mathematical laws of probability.

Task 3. Answer the questions, using the active vocabulary.

1. What are the formulas of error calculation?

2. What can be the results of making mistakes in surveying?
3. When can accidental errors occur?
4. How are regarded systematic errors?
5. When do compensating errors take place?

Task 4. Define whether the following statements are true or

false. Correct the false ones according to the text.

1. Mistakes always follow mathematical rules.
2. Even if a mistake is undetected, it does not produce a serious
effect upon the final result.
3. Accidental errors may be positive and may change sign.

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