Local attraction in compass surveying may exist due to A. incorrect levelling of the magnetic needle B. loss of magnetism of the needle C. friction of the needle at the pivot D. presence of magnetic substances near the instrument

incorrect levelling of the magnetic needle
loss of magnetism of the needle
friction of the needle at the pivot
presence of magnetic substances near the instrument

The correct answer is D. presence of magnetic substances near the instrument.

Local attraction is a phenomenon that occurs when a compass needle is affected by the presence of magnetic substances near the instrument. This can cause the needle to point in a different direction than it would if there were no magnetic substances present.

There are a number of things that can cause local attraction, including:

  • The presence of iron ore in the ground
  • The presence of electrical wires or cables
  • The presence of other magnetic instruments

If you are experiencing local attraction, there are a few things you can do to try to correct it:

  • Move the compass away from any magnetic substances.
  • Use a compass that is designed to be resistant to local attraction.
  • Use a compass that is calibrated for the area you are in.

If you are still experiencing local attraction after taking these steps, you may need to consult with a professional surveyor.

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