TESTING A THEODOLITE FOR ACCURACY

Author: Taylor E. Wilfred  

Publisher: Maney Publishing

ISSN: 1752-2706

Source: Survey Review, Vol.6, Iss.40, 1941-04, pp. : 69-75

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Abstract

When a theodolite is used to measure an angle, the result will be subjected to certain instrumental and personal errors which affect the measurement. Such errors may be accidental or systematic. Those of the former type, which follow no law and which may with equal probability occur at any graduation, are more easily eliminated, since, if a very large number of readings is taken, it is probable that the errors will cancel out and that the mean will approximate very closely to the correct figure. Systematic errors are usually due to instrumental defects and rnay be expressed as a function of the reading itself; it is the object of the manufacturer to eliminate these as far as possible, since cancellation by reiteration or by repetition is not to be expected wholly.