Compass Surveying, Basic difference between chain and compass surveying, Classification of Traverse- Closed Traverse, Open Traverse. Compass traverse, Meridian– True Meridian, Magnetic meridian, Grid Meridian, Arbitrary Meridian. Bearing, Types of bearing- True Bearing, Magnetic Bearing, Grid Bearing, Arbitrary Bearing. Designation of Bearing or Representation of Bearing- Whole Circle Bearing System, Quadrantal Bearing System.
Fore Bearing And Back Bearing, Relationship Between Fore Bearing And Back Bearing, Include Angle, Magnetic Declination, Type of Declination- Eastern Declination, Western Declination. Variation of Magnetic Declination- Secular Variation, Diurnal Variation, Annual Variation, Irregular Variation. Adjustments Of Angles, Angle of Dip, Local Attraction
Compass, Temporary & Permanent Adjustments Of Compass– Temporary adjustments, Permanent Adjustments. Compass are generally two types- Surveyor Compass, Temporary adjustments of a Surveyor’s Compass- Centring- Levelling. Permanent Adjustment of Surveyor’s compass, Prismatic Compass, Temporary Adjustments of a Prismatic Compass- Centring, Levelling, Focussing, Permanent adjustment of prismatic compass, Difference Between Prismatic Compass and Surveyor Compass
In theory of errors we details discuss theory of errors, occurrence of error, type of error, gross errors or mistakes, systematic or cumulative errors, accidental or random errors, precision, accuracy, true value, true error, most probable value (M.P.V), principle of least square, residual error, law’s of weights, probable error, error in computed result.
Compass is a survey instrument used for the measurement of horizontal angles and the bearing of a line of sight.Surveyor Compass and Prismatic Compass are discussed in detailed.