Surveying Basic Definitions
1. Meridians:
A line on the mean surface of earth joining the north and south poles is called meridian.
All lines of longitude are meridian.
2. True Meridians:
A line passing through geographical north and south poles and any point on the surface of earth is known as geographical meridian or the true meridian.
The direction of true meridian at a station is constant, i.e.
3. Magnetic Meridian:
It is the direction indicated by a freely suspended and balanced magnetic needle as in a compass, unaffected by local attractive forces.
The magnetic meridians vary with time and location.
4. Azimuths:
An azimuth is the direction of a line as given by an angle measured clockwise from north end of a meridian.
Azimuth range in magnitude from 0o to 360\(^0\).
5. Bearing:
A bearing is the direction of a line, measured clockwise or anticlockwise from the north or south end of the meridian.
It is always accompanied by letters that state the quadrant in which the line falls(NE, NW, SE, SW).
