Special Internshala Offer! Get Flat 80% Off on all Internshala Training Programs! All Courses @ Rs.999 Enroll Now!

Linear Methods of Surveying | Introduction to Surveying | By Ashutosh Nautiyal

Linear methods of Surveying can be classified into three types:- Direct method Electronic method Optical method Direct method:- The direct method is further divided into five types:- Pacing:- The pacing technique is mostly employed in preliminary surveys and explorations. In this method, the surveyor is required to conduct a rough survey quickly.

Linear Methods of Surveying 







    It can be classified into three types:- 



    • Direct method
     

    • Electronic method

    • Optical method 




    Linear Methods of Surveying | Introduction to Surveying | By Ashutosh Nautiyal
    Linear Methods of Surveying




    Direct method:-



    The direct method is further divided into five types:-


    Pacing:-




    • The pacing technique is mostly employed in preliminary surveys and explorations.


    • In this method, the surveyor is required to conduct a rough survey quickly.

    • It also roughly checks the distance measured by other means.


    • The number of paces between the two points of the line is counted.


    • Knowing the average length of the pace helps to know the length of the line.


    • The length of the pace is dependent on the person who is measuring, the ground, the speed of pacing and the slope of the country.


    • By walking on an approximate level ground over various lines of known lengths helps in determining the length of one's natural step.


    • It is a difficult process to perform pacing over a rough surface or on slopes.


    Passometer:-




    • The passometer is a watch-like instrument that is carried on the person's pocket or tied on the man's leg.


    • This instrument records the paces when the man moves from one point to another.


    • The distance is calculated by multiplying the number of paces by the average length of the pace.


    • This method overcomes the monotony and strain in counting the paces by the surveyor.


    Pedometer:-




    • The pedometer is a device similar to passometer but it is adjusted to the length of the pace of the person carrying it.


    • It registers the total distance covered by any number of paces.



    • It automatically measures the distance.


    • It is best in measuring vertical distances.


    Odometer:-




    • The odometer is an instrument that measures the number of revolutions of a wheel.


    • It is fitted to the wheel that is rolled along the line whose length is required.



    • The distance covered is calculated by multiplying the number of revolutions taken to cover the length by the circumference of the wheel.


    • This instrument does not provide accurate results on an undulating surface.


    • When the surface is smooth, the speedometer used in vehicles can be used.


    Chaining:-




    • In Chaining method, the distance is determined by means of a tape or a chain.


    • This is one of the accurate methods to determine the linear measurements.


    • The chain is used for ordinary precision.


    • Tape or a special bar is used to measure distance with high precision.


    • The distances determined by chaining form the basis of all surveying.



    • It is the accurate and commonly employed method in surveying.


    • No matter how accurately the angles may be measured, the survey can be no more precise than the chaining.



    • The instruments used for determination of the length of a line by chaining are chain or tape, arrows, pegs, ranging rods, offset rods and plumb bob.



    • Depending upon the material used, the tapes are classified as cloth or linen tape, metallic tape, steel tape and invar tape.



    Electronic method:-



    • Electronic equipment used for measuring distances is called an electronic distance measurement (EDM) instrument. 


    • They rely on the measurement of electromagnetic waves and measuring even fraction of wavelength by phase difference technique. 

    • Distances are measured with instruments that rely on propagation, reflection and subsequent reception of either radio or light waves.

    • The various instruments that are used under the electronic methods are Geodimeter, Tellurometer, the Decca navigator and the Lambda Position Fixing System.


    • The method of measurement in the case of Geodimeter is assessed on the propagation of modulated light waves. 

    • The other three instruments use radio waves for distance measurements.

    • These instruments even display the distance measured.

    • They are costly and delicate.

    • For ordinary surveying, they are not used commonly.



    Optical method:-



    • In this method, observations are taken through a telescope and distances are determined by calculation such as in tachometer or triangulation.

    • The tachometer (stadia is the common term in the USA) is a surveying method utilized to quickly determine the horizontal distance to, and elevation of, a point.

    • Stadia observations are accessed by sighting through a telescope equipped with two or more horizontal cross wires in a spacing that is known.

    • The apparent intercepted length between the bottom and top wires is read onto a graduated rod held vertically in the desired stage.

    • The space from the telescope to a rod is seen by proportional relationships in similar triangles.













    *Self Typed
    *Source- Internet, Books, Self-Analysis



    Getting Info...

    About the Author

    This is Ashutosh Nautiyal. Currently, I'm pursuing my graduation from Bipin Tripathi Kumaon Institute Of Technology, Dwarahat, Almora and my branch is Civil Engineering. I have done my schooling at Omkarananda Saraswati Nilayam, Rishikesh.

    Post a Comment

    Oops!
    It seems there is something wrong with your internet connection. Please connect to the internet and start browsing again.
    AdBlock Detected!
    We have detected that you are using adblocking plugin in your browser.
    The revenue we earn by the advertisements is used to manage this website, we request you to whitelist our website in your adblocking plugin.
    Site is Blocked
    Sorry! This site is not available in your country.