Introduction to Geomatics and Basic Surveying | Introduction to Surveying | Surveying and Geomatics | NPTEL Video | By Ashutosh Nautiyal

Ashutosh Nautiyal

Introduction to Geomatics and Basic Surveying



    Geoinformatics or Geomatics



    • Geo + information + matics



    • Geoinformatics may be defined as the measurement and management of geoinformation.



    Geoinformation: What is it?



    Introduction to Geomatics and Basic Surveying | Introduction to Surveying | NPTEL Video | By Ashutosh Nautiyal
    Surveyor





    • Any artificial or natural object/phenomenon on, below or above the surface of the earth.



    • Examples:- Land parcels, roads, topography, forest, houses, river, flooding, glaciers, etc.


    Explanatory Video:






    The fundamental divisions of Geoinformatics:



    Measurement of Geoinformation




    • Geometry: What is where?



    • Identification: What is what?



    Management of Geoinformation




    • Management (storage, retrieval and presentation) of information.



    • Manipulation (analysis based on information).



    Measurement tools:



    Primitive techniques


    It includes:-




    • Pacing, hands, guessing, rods



    • Vedic age method of pacing



    • Patwari measurement methods



    • Nali, haath, etc.



    • The human figure used mostly



    Land surveying techniques


    It includes:-




    • Using chain and compass



    • Using tape, chain, theodolite, etc.



    • This technique is cumbersome and cannot be done in inaccessible areas.



    • It needs substantial human dependence.



    Electronic land surveying techniques


    It includes:-




    • Using EDMI and total station



    • Using the robotic total station



    • This technique is fast and accurate.



    • It is difficult for inaccessible areas, as points are needed to be occupied.



    Aerial photogrammetry



    It includes:-




    • Initial uses of pigeon with the camera to spy on enemy terrain


    • Using balloons


    • Aircraft based



    • Single photograph for interpretation



    • Stereo for 3D model generation and measurement



    • Analogue > Analytical > Digital photogrammetry



    • It emerged during world war 1 and 2.



    • Still, we used to fly to collect the data every time.



    • It is a costly affair and may not be possible in bad weather.



    Satellite remote sensing




    • Commercial remote sensing is available since 1972.



    • It is done from 600 km to 900 km altitude.


    • It is used to get a synoptic view of terrain regularly in several wavebands.



    • It offers km to m level spatial resolution.


    • It is used for both measurement and identification of geoinformation.


    Global Positioning System (GPS)



    • It is an absolutely new concept to know one's location.

    • In a GPS system, there are at least 24 earth-orbiting satellites; minimum 4 needed.

    • One's position is known using the Geocentric coordinate system in a GPS system

    • It can be done everywhere where the open sky is seen.

    • It has thousands of applications.


    Applications of Management of Geoinformation



    • To store and retrieve information efficiently.



    • To present information.



    • To incorporate all information collected in analysis to suit the modern application


    GIS



    • GIS stands for Geographical Information System.



    • GIS does all the management of geoinformation.

    Examples of the use of GIS 



    Flood relief operation needs



    • Flood extent 


    • Road network and types of roads



    • Topography of land



    • Distribution of pucca houses



    • Distribution of one story or multi-story houses



    • Distribution of probable shelters



    • Locations of the rescue team









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


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