LINEAR MEASUREMENTS

LINEAR MEASUREMENTSV Vinayaka Ram

Methods of Linear MeasurementsDirectPacingPassometer (Watch like attached with leg Number of paces)Pedometer (Direct distance measurements by inputting length of the pace)Odometer (Wheel Revolutions Concept)Speedometer (Machanised odometer)ChainingOpticalElectro MagneticInstruments for ChainingChain or Tape (IS 1492-1970)Metric Chain (5m, 10m, 20m, 30m) Routinely usedGunters or Surveyor's Chain (66, 100 Links) 10 Sq. Chains = 1 AcreEngineers Chain (100 , 100 links)Revenue Chain (33, 16 links For Cadastral Surveys)Steel Band or Band Chain 20m or 30m Brass studs at every 20cm -

Instruments for ChainingArrowsPegsRanging RodsOffset RodsCross StaffPlumb BobLine Ranger

RANGING OUT SURVEY LINESDirect RangingRanging By EyeRanging by Optical Line Ranger

Indirect or Reciprocal Ranging

CHAINING ON UNEVEN OR SLOPING GROUND

Indirect Measurements:By measuring angle of inclination (Clinometers)By measuring difference of levelsBy hypotenusal allowanceDirect MeasurementErriors in ChainingErroneous Length of Chain (Cumulative +/-)Bad Ranging (Cumulative +)Careless Holding and Marking Compensating +/-)Bad Straightening (Cumulative +)Non Horizontality (Cumulative +)Sag in Chain (Cumulative +)Variation in Temperature (Cumulative +/-)Variation in Pull (Compensating +/ or Cumulative +/-)Personal Mistakes (Displacement of arrows, Miscounting the chain line, Misreading, erroneous booking)

Tape CorrectionsFor Absolute LengthFor Temperature (Tm To) L where is coefficient of thermal expansion of the tape metal Tm is the mean temperature measured in the field To is the temperature at which the tape is standardizedL is the measured LengthFor Pull or Tension[{(P P0) L} / (A E)]P Pull applied during the measurement (N)P0 Standard Pull (N)L Measured Length (m)A Cross sectional area of the tape (cm2)E Youngs Modulus of Elasticity (N/cm2)(Pull applied in the field shall be less than 20 times the weight of the tape)For SagFor SlopeFor AlignmentReduction to Sea Level etc.CHAIN SURVEYINGLinesMain Survey LinesBase LinesCheck LinesPerpendicular OffsetsOblique OffsetsLand Boundary LineWell Conditioned TriangleNo angle shall be less than 300Best Case Equilateral TriangleCONDITIONS TO BE FULFILLED

Mutual Visibility of Survey Stations

Number of survey lines shall be minimum

One or two base lines can be allowed and they must intersect in the form of the letter X

Lines must run through level ground as much as possible

Main lines must form well conditioned triangles

Sufficient check lines must be provided

Short offsets are preferred

Main survey line should not pass through obstacles

Main survey lines shall be within the boundary of the property to be surveyedCHAIN SURVEYINGField BookSingle Line BookingDouble Line Booking

CHAIN SURVEYINGTake Home Assignment 1 (10.8.2015)Explain How Latitudes and Longitudes are measured with suitable Pictorial representations. Include the applications of both latitude and longitude in detail.

Submit both word and PDF versions of assignment

Submission Deadline Closes by 12:00PM Mid Night on 17th August 2015

Late submittals will not be entertained for any reason