Local attraction in compass surveying may exist due to ..............
Aincorrect levelling of the magnetic needle
Bloss of magnetism of the nee-dle
Cfriction of the needle at the pivot
Dpresence of magnetic substances near the instrument
Aincorrect levelling of the magnetic needle
Bloss of magnetism of the nee-dle
Cfriction of the needle at the pivot
Dpresence of magnetic substances near the instrument