Module - 1 Lecture - 1 Surveying

0:13 hello so we are going to talk about a very interesting area which is basic surveying and let me introduce myself I am dr. Barath Lohani I am a faculty in department of civil engineering in IIT Kanpur and what the course of all these lectures are you talking about this basic surveying what we would like to do we would like to start this with that what is the kind of structure for this lecture stage because I have like these lectures in a modular way now what is the meaning of the model of a in this case is all the lectures are clubbed in such a way that if you take one lecture it will be kind of independent one but

1:00 to be always helpful if you can go through all the lectures so in all we have defined around thirteen main modules and in all these new modules there will be further chapters so a module is basically a major chapter in basic surveying so there are thirteen basic chapters and each chapter they will be further lectures one two five now it will it is suggested to you because when you are viewing this video that you should view these videos in a series starting from one to the end so in all there will be around 40 lectures however if you cannot do that you can still manage by viewing individual modules independently because this is

1:47 how these modules will be designed the only thing is you need some background of the previous modules so that you can understand what is there in the next module or what is in the present in any module well and all the modules also give you some introduction of days the module number one is about an introduction this is the introduction to the geo-informatics though the name of the video is basic surveying but I would like to start with this geo-informatics thing because geoinformatics is an area of which the basic surveying is a little power so we'll be talking about the concepts of surveying and the second module which

2:32 will have four lectures then we will be talking about an important area in the surveying which is the linear measurements followed by the compass surveying where we'll have two lectures then we'll be also looking into the cue the light and the total stations so these are the instruments which you make use for angle measurement a very very basic thing in basic surveying and the later on we'll be going for some control surveying that we'll cover in triangulation and trilateration then the seventh module is about labeling and contouring the seventh module of labeling and contouring is about basically the control in jet dimension or control in

3:20 vertical there is a very interesting technique of plotting the details in basic surveying and this technique is called playing table or plane tabling in sort we write it as PT so we will cover this in two lectures finally all the measurements which you take in basic surveying because there is lot of computation involved we will need to compute a lot we will need to adjust for the errors become all the measurements which will be taking or really which we'll be talking about will be subjected to some kind of error so we will need to adjust for those errors and this is very very important module or the chapter in basic surveying so please don't miss it if you are following this video lecture

4:08 well when we are talking about the basic surveying we must also talk about the maps now in the maps or in this particular module we will see what is the agency in India which can provide with the maps what are the scales at which these map can be obtained what are the prices and where firm you can purchase a map so all this will be covered in one lecture finally we will about the project surveys there we will talk about some civil engineering structures where we would like to apply these surveying whatever we learn in other modules will like to apply it day then towards the end of my video lectures we'll be talking about in 3

4:53 lectures about a technology called GPS this is a global positioning system is a new method of doing the surveying well how I have designed this course is structure and what is the objective that I am keeping in mind because when I'm talking to you through this video lecture I am thinking in my mind that you should be able to do certain things number one you should be able to understand the basic concepts of basic surveying you should be able to understand that what this area is how to do it why we do it what are the techniques what are the instruments and everything another important point you should be able to apply surveying

5:40 techniques and equipments in real life problems this is very important if you follow the video lectures carefully if you understand each and everything in the video lectures I'm sure you will be able to apply these techniques and these equipments in any real-life problem because once you are in a field you have a actual problem in front of you where the measurements are involved you will need to apply these techniques so my aim of these lectures is so you feel confident enough at the end of the lectures that you can apply these techniques another important point and that is problem solving in an optimal way while we do surveying in the field

6:27 there are many possibilities hundreds of possibilities a single problem can be solved by now out of those hundreds of possibilities which one is the best one that is the point so what we have to do we have to find a solution which is optimal optimal in the sense that optimal in terms of the cost the time the resources accuracy and all those things so by doing this course I will keep talking about this issue's time and again I'll keep informing you about the accuracies which are there the limitations of the methods the strength of the method so whenever you're in the field you are going to apply these methods you should make use of these tools which you are talking in

7:12 this course so that your solution in the field is an optimal solution and at the end this very important point now I want you to understand the pitfalls the pitfalls of this particular basic surveying when I say this I mean what are the sources of error because if you don't understand this it might happen that you will end up with your data your problem or your research with some error we don't want to do that what we want we want to do the work in the most optimal way so we have to understand that what are the pitfalls in this particular technique well so our first lecture today is about an introduction and this

8:00 is an introduction to the geo-informatics and basic serving mostly today I will talk about geo-informatics because geo-informatics is an area which encompasses many disciplines many fields of which basic surveying is a little part because we are going to talk about basic surveying so we should know where it belongs to if you are reading about the basic surveying you should know where you are ultimately going to what are the modern techniques in order to carry out basic surveying so in order to understand that we will start with the basic term geo-informatics what is the definition of Jennifer matrix the definition of Jennifer matrix is geo information and matrix as little here so

8:47 this geo plus information prismatic s-- the meaning h u stands for anything which is on the surface slightly below slightly up of the earth information information about those features which are there the surface of the earth the matrix matrix stands for measurement so we are going to be major whatever is there on the surface of the earth slightly below slightly above in addition to the measurement one more aspect of geomatics is that is the management so we measure the genes formation as well as we manage this information so this measurement and

9:35 management of G information put together it's called geo-informatics but to start with we are talking about G information what the Jennifer Mason H we should understand this as for the definition of G information is concerned we can say as it is written here any artificial all natural object phenomena on below or above the surface of the earth well some examples of that now here in this diagram or in this I can say the sketch what is the information we can find the joy information in terms of the roads or the houses maybe a tower the topography

10:25 is there the jungle the forest a water body the hedge H a playground another playground or maybe some house and the fields some other land use a land cover so this is all is the gen formation so whatever is whatever you see on the surface of the earth or we also go slightly below it or maybe slightly above it is this information now for this geo-informatics generally what I do I try to define G Informatics in two basic divisions but this is very important in order to understand

11:10 Jennifer Mattox whatever we will be doing henceforth we should understand these two fluff cervical divisions in the Jennifer Maddox what these two divisions are number one is measurement of gel formation we need to measure what is the gel formation because we have seen what the Jennifer Mason is everything on the surface of the earth so we need to measure it now in measurement also there are two parts this is very interesting and very fundamental so we should understand this first part in measurement or information is geometry we want to see what is where we'll explain it by a by an example in a moment then we also want to know that

11:58 what is what that is the identification here is an example well let us take this is the terrain or the ground and on that ground there is certain object now we this is the G information here this object is the gel formation now we want to measure this information what is the meaning of that the meaning of that is we need to define a reference system like the coordinate system shown over here and we need to fix the coordinates of this particular information this feature so we want to measure the X the Y and the JED so the moment we measure

12:44 XY jack in our reference system the G information is majored but measurement is not enough it's not enough because we need to also do another thing that what we have measured what is there on the ground what is the feature so we need to go for the identification now what is the meaning of the identification identification means what we have measured is it a tree is it a road or is it a house or a garden or a hatch or a boundary wall or the hill or the river so we need to identify this also so basically whenever we are talking about measurement of Gian formation will

13:31 these two things number one we will be measuring eight in terms of a coordinate system will fix the XYZ coordinate of it and the second thing that we'll do we'll try to identify it that what we have measured well the second aspect of geo-informatics because I was saying that Jennifer matrix has got two fundamental divisions one is the measurement of G information the second one second one is about well take it like this we have majored the information we know the XYZ coordinates of a particular feature we also know what the feature age but what to do of this what to do of this information so

14:16 the second aspect of the information age of the Jennifer Mattox is management of G information as we have written here in the slide we want to manage the information because just measurement identification is not enough now for example here if you look at the slide here in the previous slide we are talking about the measurement of the information and now here we are talking about the management of the information the management means all the things which we had measured we had identified we are trying to plot them here as you can see in the slide using a map so we are retaining them for our used later on

15:01 we are storing the data in a particular format what we had done for example in this map we had measured there in the ground all the roads where they were we also identified what are the roads where they are leading to we also identified where are the fields we also identified where are the areas which are occupied by houses so our measurement and identification was complete so the management of this information means we want to put this information in such a way so that we can store it properly not only storing we want to retrieve this information later on so the retrieval now with this map what we have done we have restored the

15:46 information in the form of a map anytime you want to know about the math you want to know about the G information what you need to do you just take the map out start looking at the features so what you are doing you are retrieving the information from the map and then the presentation of course the map is an way of presenting this information we could have presented this information what we majored in the ground maybe some other way also for examples the names of the roads their lands so we could have made a table so that is also a way of presenting this information or maybe managing this information but our information here is the geo information geo means which is spread in the terrain

16:32 which then spatial information so we want to present it in such a way so that information retains its own characteristic that the information is presented also in a spatial way and this is how this map comes into the picture now another aspect of management of G information is manipulation now as I'm writing here in the slide manipulation is analysis of geo information so that we can come out with some results some answers one example here could be as we can see in this map let us say I want to start from a particular Junction in the town and I want to reach the other

17:18 Junction here in the town well throughout this street network there are various possibilities you can take a route well like this or you may like to take a route like this it's a question age which of these two routes is best so what you need to do you need to analyze this information you need to do some kind of network analysis in your information so that is also a part of geo-informatics so what we do in gelfoam Attucks we measure the gen formation from the field we measure it by record the coordinates XY jet and we also identified the information that what we

18:05 have measured then we come to the office we present them this information we store the information in such a way either in the computers or in the form of the maps so that we can drive it later on we can present it in a proper way and also with the help of the information we want to analyze the information so that we can arrive at certain results well how do you said that as I was saying that we have to measure the G information and we have to manage the information so what I will do I will give you a brief introduction of the tools which we use for measuring geo information and when I am talking about this we will talk about these measuring

18:51 tools for G information in the way they were developed so we will start from the very very primitive times how people used to measure it and we'll come to the latest things that how we are measuring the G information now well usually the primitive techniques as we all know is still if you go to the villages you will find people doing it we use either pace pace means you walk along or maybe you use the hands you know you say polished okay a particle length is so much you make use of a hand then you measure it or maybe you make a guess or maybe you also make use of some rods some standard rods

19:36 so these are the primitive ways of measuring the distances there are some very good examples in Vedic age methods of pacing I'll give you an example right now and for that I will need to change the slide so we are here in the in your slide and what in the Vedic is people used to do I will give you just one example of the pacing let us say this is the ground and they would like to measure the quality of the soil so what they would do they would dig a hole there on the soil or there in the land and they would fill it with water so this hole has been dug and the soil

20:25 is kept out and now it is filled with water now in order to measure the time what they would do a person who is doing this job or maybe another person he will walk to his site for example let's say five hundred paces so he will do the spacing hundred times he is at a certain distance and from that point he'll come back when he comes back they will check again that where is the water level now depending how much the water level has gone down they will come to know about the soil so basically why I'm talking

21:11 about this I'm talking about this because the people who are making use of pacing measuring distances amazing time using the human body in Vedic is also now I will go back to our previous slide so we talked about this just was an example how people were making use of the human body from measuring distances another one you must have seen in villages this is very quite common the part where is who is the grassroot level worker in a village who measures the lands there they also make use of some devices may be in a form of a rod or

21:57 some chain in order to measure the land parcels so that that is also you know I would like to say quite primitive way of measurement then if you further go into the villages still people they measure their land the area using for example the nollie and Hart so these terms may differ I am writing nollie and hard because the area from where I belong to people use this okay particular area is one alley or to nollie that kind of thing now how it is related with the area of the ground is how much wheat or rice will be produced in that particular area so this is how a relationship is there in how much wheat

22:44 is produced from a particular field and this is how they are coming to know about the area so what we observe in most of these cases the human figure was used either the pace the hands of these things now after some time when people started requiring accurate measurements what they thought that the human body was not good enough because all humans they differ in their measurements so if someone a distance 100 paces for other person who is shot in hide that distance could be hundred 20 paise so they wanted to standardize these things so some new methods came for making these

23:30 measurements so that was the time when the land surveying measuring the land started so the standard methods of measuring distances are change or maybe tape at the same time people also wanted to measure the angles because in order to determine the area you also need the angle here is one instrument which is called compass it's a very simple instrument and it works in the principle of magnet magnetic needle so there is a magnetic needle which will align itself in the magnetic field and making use of that it is possible that we can measure the angles so people started making use

24:16 of compass also some more instruments for example the theodolite this is also an instrument which is used for making the measurements of angles in a more sophisticated way more accurately however the problem with the land surveying methods watch in most of the cases these methods are very cumbersome as I'm writing here in the slide they cannot be done in inaccessible areas now what you need to do you need to go to that area and you need to occupy the point then you need to carry out the measurements so all these methods are kind of very very cumbersome they will take long long

25:03 durations in order to complete the survey so considering this time people started thinking of some other method so the other methods came in the same form of land surveying but with the development of electronics what people started doing they converted these instruments which were conventional mechanical instruments earlier into the electronics Tremont's as it is written here we have the methods now which are mostly relying on these tremaine's which make use of the electronics and in this case we have the instruments for example the EDM I it's an electronic distance

25:49 measuring instrument now to measure the distance you need not to do the pacing you need not to spread the chain but what you need to do you to simplifier an electromagnetic pulse and it will tell you the distance so these instruments are very very sophisticated also as seen here in the slide we have a total station this total station can measure angles can measure distances all automatically without much involvement of a human being so now the things have become very very fast it can do very a creates a way it can do them very fast there is another word which you see here in the slide it says robotic sometime

26:38 back the total stations were like that that a human being has to operate it but now the total stresses are developed to such a stage that the total station is kept in a place independently the surveyor moves with a rod which is also a part of the total station everywhere in the ground total station will target that towed automatically the surveyor who is moving with the rod will just press some buttons and with the press of those buttons the total station will carry out the measurements so it's really very fast a single person can do the surveying however in these electronic methods also as we see here in the slide there is still difficult

27:26 difficult because you have to go to the ground you have to occupy the point I'll give you an example let us say you want to measure for a power line this is the power line between two poles you want to measure the coordinates of several points there in the power line if you need to do it using the total station it's a very difficult exercise because you need to pass at each and every point the another example if you want to measure let us say an area which is flooded it's very difficult to go to that area you cannot occupy the points there because everywhere it is flooded so you cannot carry out the measurements what you need to do you need to wait so that the flood water will recede then you will go to the ground occupy the ground

28:12 then carry out the measurements so in all the methods that we saw so far either the primitive ones land surveying ones or the electronic suffering one in all the cases you have to go to the ground occupy the ground and then take the measurements so which is really difficult in case of difficult terrain in case of inaccessible terrain so considering this people started thinking of something more some new measurement tools came for measuring the geo information and here is one which I am writing in the slide that is the aerial photogrammetry as seen here in the picture in case of the aerial photogrammetry once it was developed

28:58 initially during the time of the World War World War one and two people used it for a spying purpose what they would do they will fit a camera in the belly of a pigeon and the pigeon will fly in the anime terrain and it will take a single photograph and it will come back so it was a really nice way very smart way of taking the photographs from the air in this anime area so you have all the information about the anime movement so this is how the aerial photogrammetry developed have a later on we have started making use of balloons and as well as aircraft based what we do now I am going to give you an

29:45 example in the case of the aircraft the aircraft will fly at an altitude of for example two thousand meters three thousand meters four thousand ten thousand depending what kind of application what kind of photographs we are looking for so while the aircraft is flying over the ground it will take an image it will capture one photograph of the ground the aircraft moves further it will capture another one so like that a series of photographs will be captured for the terrain and these photographs we say aerial photograph as you can see here in these aerial photographs we have some area which is overlapping will make use of this in a moment

30:30 now these aerial photographs could be either a single photograph as we see here this is a single photograph of the terrain and you know in this you can see the road the vehicles from the road houses the tree each somewhat a pond so we can now identify the things one aspect of the information not only that if our photographs are stereo stereo means as you are talking in the earlier case two overlapping photographs from two positions of the aircraft we have the area which is common in two photographs so that kind of photograph this photograph and this photograph put together we say stereo pure so if we

31:18 have the stereo pair or the steerer four Graff it is possible to generate three-dimensional model of the ground now once you can generate a three-dimensional model of the ground what is the meaning of that the meaning of that is you can now start measuring on that 3d model various things you can measure the distances you can measure the coordinates you can measure the angles so with the help of the photograph as we are looking here we can measure the XYZ coordinates you can identify the things so we can get our all geo information that we need to this aerial photogrammetry also developed like anything earlier we had some analog

32:03 way of taking the photograph also processing them in between came the analytical way and now the modern one just for your information is the digital photogrammetry where most of the things are automatic now however as we are writing here still we need to fly to collect the data every time whenever you need the data you need to fly with the aerial photograph and this is not always possible why it is not possible because for example some area is flooded and you need to take Adel for the graph of that area because you want to see how much of the area is flooded you want to take the measurements so in order to measure this

32:51 you need to fly using your aircraft now the problems the aircraft may not be available or the aircraft where it is available may be very very far from the site where the flooding is taking place so it's really very difficult to fly every time you cannot do it immediately in many instances the second thing even if you can fly every time it's a costly affair aircraft they cost a lot the crew will cost a lot so it's a costly affair so though the aircrafts were able to give us very fast very accurate and we really snob take everything on the ground you know formation we had some limitations from the ADA for the commentary' aerial photo geometry it is

33:38 being used now depending upon the application but people started thinking something more well can there is something in this space which can go around the earth can take the observations regularly and the idea of satellite came in mind so the satellites are such things as you can see in the slide they will rotate around the earth they will keep rotating around the earth and they will keep taking the images of the earth they take these because while the satellite is rotating is orbiting the Earth will spin so it is possible the arrangements are such that that the images are taken all over the earth everywhere so what do you have you have now a system which can take the images

34:23 repetitively after five days after 10 days depending the satellite so this satellite remote sensing it actually started commercially I'm saying because there were some spy satellites earlier also the date of those satellites was not available earlier to the civil users so this commercial remote sensing it in fact started in 1972 with a satellite that was called Landsat sorry about that land said that was a satellite by United States and this data was available to the civil users generally these

35:09 satellites which we use for the Earth observation they will be from 600 kilometer to 900 kilometer altitude so from those altitudes you just think of that you know these are very very high altitudes the satellite is orbiting there and you are able to capture the images of the earth so what you captured from the satellite may be a case like this now here in this a satellite has captured an image of European countries while we can see the Africa also there they're not part of the Africa you can see the United Kingdom part of the Europe in dark because it's animates of evening time part of the euro here in the UK the London the other land they are still

35:57 towards the evening it's not dark there while in other parts of France and other parts we can see the lights on so satellite which are at very high altitude can capture images like this now this kind of view of the satellite because it is capturing in one view everything whatever is there and in whose area we said this a synoptic view of the terrain but this kind of thing was not possible earlier if you are doing land surveying if you're doing aerial photogrammetry also this was not possible then the second aspect satellites also take images in several wave banks what is the meaning of this the meaning is it doesn't take the image

36:44 only in optical it can take images it can take the photographs or the imagery is also in microwave now if there are some cloud covers over the area for example let's say in this slide there are some cloud covers these are the clouds if we are taking the image in optical then because of the cloud we cannot observe the ground in the satellite image will have only the cloud so if you are using if you are using the microwave remote sensing it is possible that you can see beneath the cloud so there is a term called spatial resolution in satellite remote sensing

37:31 earlier this art allows the commercial satellites also they had a special resolution of 80 meter now what is the meaning of that to understand the meaning of that you need to see this slide in this slide is a synoptic view we can see the entire continent but we cannot see the individual streets here we cannot see the individual houses so the resolution of data is very poor however in this light I just see you can see the individual cars on the road the house is bridge maybe some boots here some more cars individual page so

38:20 everything is clearly visible now this is the data from icon of satellite the resolution of this satellite is 1 meter so we have in commercial arena some satellites which can give you the resolution varying from kilometer to meter so it depends what kind of your application H if you have picking demands use areas big areas then you will go for resolution in called kilometer your application is something like in a forest mapping you don't want to measure each and every tree your area you want to measure the entire extent of the forest so it is advisable not to go for a data which is very accurate

39:07 the resolution is only one meter or half a meter but if your application is you want to measure the individual cars on the road you want to measure the outlines of the buildings you want to measure where exactly the trees are you want to measure what is the outline Bolivar exactly very accurately so for most of engineering applications we need accurate measurements so it is possible that we can get these accurate measurements with the satellites which have a spatial resolution of order of one meter or slightly around so we have at the moment the best resolution commercially available of around half a

39:54 meter so it's a very very good resolution you can see many details a lot of information in the data now this satellite data also because we are talking about I will take you back again to what we started with we started with the geo-informatics basically two divisions measurement of the information and management then in measurement of djenne formation again two things where the information is that is the XYZ coordinates the second thing what the information is so we can make use of satellite data as we can see in the slide for both the purposes we can do the measurement here and also we can do

40:40 the identification well you can identify in this figure the bridge buildings roads cars everything now with some process which we doing remote sensing it is possible that I can assign coordinates also to each and every point not only in x and y but also injured so by that measurement you move the XYZ coordinates also of each and every point so if you want to measure the distance along this road the distance is known to you so now see how the things have changed earlier you are supposed to go to the ground occupy this point but now

41:25 you are not going to the ground rather you are making use of satellite image and you take that image satellite image you can measure the distances you can also measure the angles for example the angle between these two streets what this angle H so we can make use of satellite remote sensing for both measurement and identification another interesting thing I just wanted to show you because this is very important data the satellites do you take repetitive data as I told they will cover your earth every fifth day nine day it is the 22nd day depending which satellite we are talking about here is a data from digital globe the name of the satellite

42:11 is kid Berg and the resolution is half a meter this is the data from Indonesia and is the data just before the tsunami of 26 December 2004 so this is the area which was the area used to look like this before the tsunami with the houses please the tree each mode fields houses the jungle now after the tsunami again the satellites they captured the data now how the data looks like the data looks like this both here and here both are same so we can

42:57 see the areas which have been flooded now so you can do this mapping very quickly using the satellite all the areas which have been flooded you can also make use of this data in order to see the damages to the buildings all the buildings have been damaged one little building over here this to the roof is intact so we can guess this this building deal damage while for all other buildings they have been damaged you can see the debris I believe where the debris is falling so this is all you know we can make use of satellite image in order to collect the information for measurement of the Jean formation as well as management we'll talk later on but for the information knowing where it

43:46 is also knowing what it is one more modern tool this is a model tool which we say the GPS Global Positioning System now what this GPS is this is the beginning itself we always wanted to know where we are okay in the Vedic age also people found some ways to know where they are they made use of the Stars the Sun the moon and all those things we wanted to know our location because our location is very important to us because you want to see the my ideal location in relation to other things so the GPS is the instrument

44:31 which can give once location very accurately what the GPS is in the case of the GPS as you can see here all around our earth we have around 24 I am saying 24 at the moment though it's not exactly 24 it's more than that number of GPS satellites and these satellites are orbiting the Earth in such a way that at any moment of time if you are standing anywhere you can see at least four satellites of course more than that what you have you have a receiver the receiver of the GPS may look like this or maybe it with a

45:17 simple handheld device like the mobile phone this is your majors your distance to four satellites as you can see here so there is a method we will see this method later on so by knowing these four distances also by knowing the location of these satellites exactly at the time when we are measuring the distance in a coordinate system which you define at the center of the earth it is possible for us that we can determine where this receiver H so whether you go on the surface of the earth you're standing here by using the GPS receiver you

46:04 should be able to determine where you are in this coordinate system it's a very good instrument that little instrument which has a size of only a mobile phone you go about with this anywhere if you're walking with the system and it is possible because this receiver is measuring the distances to four satellites and immediately by the computations are we come to know where I am what are the latitudes longitudes and altitude of the point where I am standing so anywhere you go around the earth this is possible now what you can do if you know the latitude of this place of this space all the coordinates latitude longitude and altitude of two points on the surface of the earth you can measure

46:50 the distance between two points if you know the left long and altitude of a third point also you can also measure the angles well some more points you can find the area so now with a single GPS as you move your coordinates are being lasered automatically and independently so you know the coordinates of this point coordinates of this point coordinates of this point coordinates of this point and if you know the coordinates of all these points the area of this field is known to you so it's a very interesting way of carrying out the measurements and a very

47:35 very modern way now as we are saying they are at least 24 satellites which we need to make use of and the coordinates are given I am going to give your term here which is called geocentric coordinate system the meaning is the center of the coordinate or the origin is at the center of the earth so all the coordinates whether you are going with the GPS receiver will be measured in this protocol coordinate system now about the global posting system it's very fast if you want to take slightly less accurate

48:21 measurement okay you can just run you can you are in a car you're moving in a car and the GPS with you which is in the car is looking at the satellites measuring the distances to the satellites and finding a locations if you want to do it very very accurately say in millimeter level you want to do it very accurately for some applications for example in the case of the earthquake where let us say I am drawing this diagram this is a fault and there is likely hood of a movement along this fault let's say I draw it this way so we need to monitor this fault is any movement taking place there so

49:09 what people are doing now several researchers they are putting the GPS GPS one GPS two similarly here also three four and so on so what we have we have a network of gps's which are kept along all along the fault line so we have a network like this now if there is any relative movement in between these two plates so these points will move in relation to these two what the GPS is giving us GPS is giving us the coordinates regularly so we know the

49:57 coordinates of this so we know the distance or rather I can say we know this vector so between two points I know the vector now this this was my initial vector now this initial vector may change after some time so this change in the vector in terms of the angle in terms of the distance it's because of the relative movement of these two plates so people are trying to make use of this kind of observation the GPS observation in order to predict the earthquake now another thing another good thing about the GPS you can use it everywhere all over the earth wherever

50:44 you can find open sky you cannot do it inside the room because you need to see the satellites so because it gives you a location there are thousands of applications which are possible and many more applications are being invented GPS is going to be an essential part in many Mobile's nowadays the GPS are there even in many watches people are put wearing the GPS in their watch if someone is going to a forested area they want to go to you know they want to go to a forested area so they're in the forest they want to locate where they are moving they carry a handheld GPS of the size of a mobile phone and it keeps telling you okay you

51:29 are moving in this direction if you want to come back look at your movement how you had reached a particular point so you have to just backtrack so all these things are possible with the GPS now having seen all these as initially I talk for the geo-informatics there are two fundamental divisions one measurement of G information now whatever we have discussed so far the primitive techniques land surveying electronic surveying aerial photogrammetry satellite motion sensing or the GPS all these are the methods for taking observations from measuring geo information also all these are the

52:16 methods by which we can not only major XYZ of the G 'information but we also know about what they are now the next expect once we have measured this information we want to manage it we want to store it properly so that's the second aspect or the fundamental division of geo-informatics area which is the management of the information so as we saw a little bit earlier also we need to store our data there is a requirement to store the data there is a requirement for the tracking the information we want to store it properly and whenever we need it we need to drive

53:02 it we need to get it back so that is the management of the gen formation we also need to present the information what is the meaning of that whatever you have accumulated whatever you majored in the field you need to present it maybe you want to make a map maybe you want to make a table maybe you want to make an extend you know you want to give to a leader a political leader you want to show you okay how much of the area is flooded he is interested in that so do you use the map of the town on top of that you want to draw a line which shows the area which is flooded so that's the information presentation so that is also

53:48 a part of the management of Jian formation most important of all because storing the driving presentation these are important aspects but the most important of all is whatever the information you have is stored with you you want to analyze it you want to put all these information together so that you want to come up with some kind of final answer one one one thing could be one example let us say we have a map of an area and in that map we have the topography sown I'm just drawing it this way right now we have some pre age we have the house age everything we have some villages

54:39 here you know having those houses and all that fields pools reword everything now your job is you want to start from a point a and you want to reach point B so far there is no road in between a and B so what you do you want to join in B by a road so there are various possibilities you can join them or by a road which may go like this you can join them by a road which may go like this which way what is the best way so what you do you make use of the G information which is collected so for a problem like this the Jew information could be the geology of the area the rock type where

55:26 the villages are where the trees are where the fields where the schools where the towns all this is the G information so you put all this information together and then your computer where this information is kept and lies is this in order to find the best possible route alignment between these two points a and B so that is an aspect where we do analysis of the gene formation now in transformation there is a term which is called G is JH stands for geographical information system and this G is does all this management part whatever we are talking about everything will be covered in GIS now I would like to end this

56:15 presentation by one example of the GIS and this is the example H there in some town there is the flooding and we need to locate the areas where we need to provide the relief this is a very important decision you want to provide the relief in those areas where it is required now if this is the problem now start thinking in order to answer this problem to provide relief to those areas where the flood is what all information we need what was information we need so the G information that we need okay how much area is flooded we need to measure it how do we measure it we can make use

57:01 of the satellite or we can go to the ground if possible map it we need because we have to provide the relief we need to know what is the route that work in the area and what are the types of the road what is the chance that a particular type of road has been washed away we need to know about the topography the why topography we need to know about the topography the courage those areas which are elevated if we know that the space of the river or the height of the flood water is so and so so we can make an assessment what all areas will be flooded if we know the

57:47 topography of the land so graphing means the undulations so those areas which are higher will not be flooded we need to know about the Parker houses if you know about the Parker House of the school buildings and building there so we know well these are the buildings which will not be damaged so the chances are people are occupying these buildings because these are not damaged okay so distribution of where the one-story and multi storey houses are we need to know the probable shelters where the people are really staying in the event of the flood so having known all these

58:33 information there is an requirement now to take a decision where all this information will be put and a decision will be taken on the basis of this G information so what we need to do we need to put all this information in a model now this model will run under GIS it will make use of all these information to find the sides on priority basis for the rescue so we will need a model and that model can be run on this GIS data that you information so this is the management part of the G information where we are coming out with the areas yes this is the area where the

59:18 rescue has to be provided this task if we do it manually is a very difficult task so Mendel interpretation is involved and a conventional method scionworld which are very very difficult to carry out so carrying out carry out this task in a computer using yes is suggested now finally whatever we have done today in our next video lecture we will talk in detail about the basic surveying because today we saw that what the geo information is what is G informatics and tomorrow we'll see what the basic surveying is though we saw about it a little bit today so this is what we'll

1:00:04 cover in our next video lecture thank you