Some terminologies
a) Turning point: An intervening point between BMS upon which a back sight and a fore sight are taken.
b) Magnetic meridian: Imaginary line connecting the North and South poles.
c) Tie line: Line joining two fixed points on the main survey line.
d) Swing offset: Swing offset is taken by swinging a tape about the point as a center and measuring the minimum distance from the point to the line.
e) Hypotensual allowance: A correction is applied in the field at every chain length and at every point where the slope changes. It is known as hypotensual allowance.
f) Offset: A short distance measured perpendicularly from a main survey line is called offset.
g) Magnetic Bearing: The angle made by survey line with respect to magnetic meridian I called Magnetic bearing.