Correct Answer - Option 1 : Parallax
Explanation:
The sources of errors in stadia measurements are as follows:
Instrument errors
Personal errors
Errors due to Natural Causes:
-
Unequal expansion of the instrument parts
-
Unequal refraction and
- Bad visibility
- Due to wind
Errors due to Instruments:
- Imperfect permanent adjustments in the instrument
- Incorrect graduations on the stadia rod
Errors due to Manipulation and Sighting or personal errors:
- These errors depend on the efficiency and skill of the surveyor and due to inaccurate leveling and centering of the instrument
- These errors may occur and by these incorrect stadia, readings are taken.
So, Parallax is not an error due to natural causes.
