The following test should be remembered in survey.

1. Azimuth test: It is done to make the line of sight perpendicular to the horizontal axis.

2.  Spire test: It is a test carried out to remove error due to non-perpendicularity of the horizontal axis and the vertical axis in surveying Instrument.    

Key Points :-

Permanent adjustments of theodolite:

• Adjustment of plate level

• Adjustment of line of sight

• Adjustment of horizontal axis

• Adjustment of altitude level and vertical index frame.         

3. Cross- Hair ring test: This test is done to make the vertical cross-hair to lie in a plane perpendicular to horizontal axis.

4. Vertical arc test: It is done to make the vertical circle indicate zero when the line of sight is perpendicular to the vertical axis.