2.1 COMPASS SURVEYING
ANGULAR MEASUREMENTS – NECESSITY – INSTRUMENTS USED –
PRISMATIC COMPASS: CONSTRUCTION DETAILS, FUNCTIONS AND
TEMPORARY ADJUSTMENT – TYPES OF MERIDIANS – TYPES OF
BEARINGS: WHOLE CIRCLE AND REDUCED BEARINGS, FORE AND BACK
BEARINGS – COMPUTATION OF INCLUDED ANGLES FROM BEARINGS –
COMPUTATION OF BEARINGS FROM INCLUDED ANGLES – PROBLEMS –
LOCAL ATTRACTION: DETECTION, CORRECTION AND PROBLEMS – DIP
AND DECLINATION – COMPASS TRAVERSING – ERRORS IN COMPASSG
LEVELLING – DEFINITION – LEVEL – PARTS – FUNCTIONS –
ACCESSORIES TYPES OF LEVELS : DUMPY LEVEL, MODERN TILTING
LEVEL, QUICK SETTING LEVEL, AUTOMATIC AND LASER LEVEL –
LEVELLING STAFF – TYPES -COMPONENT PARTS OF LEVELLING
INSTRUMENT DEFINITIONS OF TERMS USED : LEVEL SURFACE,
HORIZONTAL AND VERTICAL SURFACES, DATUM, BENCH MARKS,
REDUCED LEVEL, RISE, FALL, LINE OF COLLIMATION, AXIS OF
TELESCOPE, AXIS OF BUBBLE TUBE, STATION, BACK SIGHT, FORE
SIGHT, INTERMEDIATE SIGHT, CHANGE POINT, HEIGHT OF INSTRUMENT,
FOCUSING AND PARALLAX – TEMPORARY ADJUSTMENT OF A LEVEL –
BALANCING BACK SIGHT AND FORESIGHT – PRINCIPLE OF LEVELLING –
SIMPLE LEVELLING– THEORY OF DIFFERENTIAL LEVELLING (FLY
LEVELLING) –LEVELLING FIELD BOOK – REDUCTION OF LEVELS –
HEIGHT OF COLLIMATION AND RISE AND FALL METHOD