Surveying
In triangulation surveys

The area is divided into triangular figures
All listed here
Sides are not measured excepting the base line
Control stations are located from which detailed surveys are carried out

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Surveying
The error due to eccentricity of inner and outer axes can be eliminated by

taking both face observations and taking the mean of the two
reading both verniers and taking the mean of the two
taking mean of several readings distributed over different portions of the graduated circle
double sighting

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