Basic Concepts of Surveying | Part 1 | Introduction to Surveying | Explanatory Video | Surveying and Geomatics | By Ashutosh Nautiyal

Ashutosh Nautiyal

Basic Concepts of Surveying (Part 1) 



    Surveying



    • Surveying is defined as the art and science of obtaining quantified and qualified measurements, the interpretation of these measurements and a meaningful presentation of result.

    • Surveying is the collection of data or information.

    • We are concerned with the surveying of geoinformation:

               For engineering projects

               For geographical mapping



    • In surveying, there is a need for a reference system for fixing relative positions of points.


    Basic Concepts of Surveying | Part 1 | Introduction to Surveying | NPTEL Video | Surveying and Geomatics | By Ashutosh Nautiyal
    Basic Concepts of Surveying (Part 1)



    Examples where Surveying is needed:

    • Construction of a building



    It includes:-




    • Site selection



    • Knowledge of topography (Map)



    • Planning building on it



    • Transfer building onto the site



    • Town planning

    It includes:-



    • Site selection



    • Knowledge of topography (Map)



    • Planning town on it



    • Transfer the town onto the ground



    • Euro Tunnel



    • Deformation of a dam



    • Bridge planning



    • The tilt of a tower (Taj Mahal)



    • Artillery bombing



    • Missile



    Explanatory Video









    Surveying: Two categories 



    • Surveying 


    Bringing the ground/terrain in laboratory/office for working upon it.


    • Laying out 


    Taking the work onto the ground as per design specifications.


    Reference System for measuring Geoinformation of the Earth Surface




    • X-Y plane (it can be used only for a mathematical surface).



    • Geoid (everywhere in this surface, the potential is the same).



    • MSL or Mean Sea Level (it is a geoid which is the average surface of the sea and it is measured over a period of 19 years).



    • Ellipsoid



    There are two types of Surveying:



    Plane Surveying




    • The surveying in which the earth's surface is considered to be flat.

    • For a 20 km distance in the x-direction, the difference in distances between the arc and the corresponding chord will only be 10 mm.

    • For a 20 km distance in the z-direction (or the geoidal height), the difference in distances between the arc and the corresponding chord will be 16 m which is a significant value.

    • Plane surveying can be done for making a planimetric map which is only plotting X and Y (not Z or geoidal height).


    • These surveys deal with areas of limited extent (areas less than 200 km2).


    • For engineering projects like bridges, factories, dams, canals, railways, highways, etc. plane surveying is done.



    Geodetic Surveying 



    • The surveying in which the earth's curvature is considered.


    • A higher degree of precision is exercised in linear and angular measurements in geodetic surveying.


    • These surveys extend over large areas (such as a State or a Country).











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

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