Surveying
SURVEYING, Classification of survey based on the curvature of the earth surface- Plane Survey, Geodetic Survey. Classification of survey based on Place– Land Survey (Topographical Survey, Cadastral Survey, City Survey), Hydrographical Survey, Astronomical Survey. Classification of survey based on Purpose- Engineering Survey, Military Survey, Archaeological Survey, Mine Survey, Geological Survey. Classification of survey based on Instrument- Chain Survey, Compass Survey, Levelling, Plane table Surveying, Theodolite Survey, Tacheometric Survey, Photogrammetric Survey, EDM (Electronic Distance Measurement) Survey. Principal of surveying– Working From Whole To Part, Location of a Point by With Respect to Reference Point. Instruments Used for Various Types of Measurement.
Plan & Map, SCALE, Representation of Scale- Engineer’s Scale, Representation Fraction (RF), Graphical Scale. Shrinkage Factor or Shrinkage Ratio, Error Due to Shrinkage of Map, Error Due to Wrong Measuring Scale, Type of Scales- Plane Scale, Diagonal Scale, Vernier Scale (Direct Vernier, Retrograde Vernier, Extended Vernier, Double Vernier).
Linear Measurements, Procedure in Chain Surveying,Basic Definition of Chain Surveying- Main Station, Tie Station, Main Survey Line, Tie Line/ Subsidiary Line, Base Line, Check Line/ Proof Line, Offset, Chainage, Well Conditioned Triangle. Linear Measurement with Chain- On Smooth Level Ground, On Sloping Ground. Errors & Correction in Chaining/ Taping, Type of Error in Chaining, Correction in Chaining & Taping Are Following Type- Correction For Standardisation, Correction for Slope (Cg), Correction for Pull (Tension), Correction for Temperature (Ct), Correction for Sag (Csag), Reduction of length to mean sea level (MSL), Field Work in Chain Surveying- Reconnaissance, Marking of Stations, Running Survey Lines, Taking Offsets. Limiting Length of Offsets- Error only in laying offset, Error in laying direction and liner measurement.
Equipment Used In Chain Surveying, Surveying Chain, Types of Chain- Revenue chain, Gunter’s chain, Engineer’s chain, Metric chain, Suitability of Chain, Unsuitability of Chain, Units of Measurement, Tapes-Cloth or Linen Tape, Metallic Tape, Steel Tape, Invar Tape, Pegs, Arrows, Ranging rods, Offset rods, Plumb bob, Clinometer, Cross-staff, Optical Square, Prism Square, Chain Survey Instruments, Distance Measuring Device, Instruments Used for Various Types of Measurement
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
Traverse Survey, Types of Traverse- Closed Traverse, Open Traverse. Method of Traversing– Linear Measurement, Angular Measurements: Loose Needle Method, Fast Needle Method, Method of Included Angle, Method of Direct Angles, Method of Deflection Angles. Balancing the Angle of Traverse- Average Correction Method. Latitude And Departure- Latitude (L), Departure (D). Checks in a Closed Traverse- Loop Traverse, Link Traverse. Closing Error, Relative Error of Closure or Relative Precision, Method to Correct Clothing Error- Bowditch’s Rule, Transit Rule.
Levelling, Important Terminologies In Levelling, Elevation & Altitude, Reduced Level, Mean Sea Level, Bench Marks(B.M)– G.T.S Bench Marks, Permanent Bench Marks, Temporary Bench Marks, Arbitrary Bench Marks. Measurement in Leveling Work- Horizontal Line, Vertical Line, Level Line, Back Sight Reading, Fore Sight Reading, Intermediate Sight Reading. Method to Find Reduced Level- Height of Instrument, Rise and Fall Method. Inverted Staff, Correction Required in Levelling Work- Correction due to Earth Curvature (Cc), Correction due to Refraction (CR), Combined Correction due to Both (C). Distance of Visible Horizon- When height of any one point is considered, When height of both points are considered. Reciprocal Leveling – When the instrument near A, When the instrument near B, Collimation error– When Area is Large, When Area is small, Angular / Inclination Error, Sensitivity of Bubble Tube , The sensitivity of level tube increases with?.
Introduction, Measurement of Area: Computation of Area of Geometrical Figures- Rectangle, Square, Triangle, Circle, Parallelogram, Trapezoid, Trapezium, Oblique Triangle, Area of a Segment, Regular Polygon. Computation of Area of Irregular Shape– Mid Ordinate Rule, Average Offset Rule, Trapezoidal Rule, Simpson’s One Third Rule. Measurement Of Volume : Computation of Volume of Irregular Shape– Trapezoidal Rule / End Area Method, Prismoidal / Simpson’s Rule
Tacheometry, Instrument Used In Tacheometry – Tacheometer, Stadia Rod. Different Systems of Tacheometric Measurement- Stadia System (Fixed hair system, Movable hair system), Tangential System, Subtense Bar System, Theory of Tacheometer, Distance and Elevation Through Tacheometer- When a Staff Is Vertical, & When a Staff Is Perpendicular to Line of Sight.
Topics
In special instrument, we detailed discuss about hand leveling, abney level, indian pattern clinometer, ceylon ghat tracer, sextant, site square, mining dial, brunton’s compass, pantagraph, eidograph.
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.