 overview of the remote sensing technology. Now, what we understand by remote sensing as the name suggests we are sensing something remotely without touching the object. So, basically you know the our vision is also a kind of a remote sensing you do not touch the object to see it right or a camera technology is a remote sensing where we can print of the particular object in front of us without touching. So, the same technology is a known as a remote sensing technology where we use a specific sensor instrument to gather the data of the earth surface and that sensor is mounted on a suitable plate from at a distance from the object. So, we do not touch the object, but we take a particular picture basically of that particular object without touching it with the head of some sensors. This is known as a remote sensing technology, this is very useful. Basically this remote sensing technology is a source of data to your GIS geographic information system and the data will pass in our decision making process. It supports the decision making that is why it is so important. Now, let us have some overview on this the images generated by the remote sensing technology right. This is the island in Indonesia in 2004 before Sunami it is a very high resolution you know you can see the buildings. This is a remotely sense data it is a picture basically image collected by a specific satellite I am coming to it. Now, this is after Sunami can you see the difference then you will be able to assess the damage without going to that particular location with the help of this picture you will be able to get the you know the changes. Like this is east coast of India the Sunami event right. So, around this can you see that 2000 December 2004, 26 December 2004 and 4 January 2004 can you see the previous and the next after the Sunami entire island got inundated. So, these differences can be identified and you will be able to analyze what is the damage. So, this is the use of this technology this is very you know very very useful very strong though it is a very recent science, but this is very useful now it is supporting the decision policy makers are very you know getting the help from this particular like this is 911 Patagon before and after the attack. Can you identify this this is Mumbai airport now next name is Aircrafts Park in the airport this is Agudhavi you can see the cars there very high this is Dubai. Can you identify this? This is Taj Mahal and it is surrounding Afri tower Ladakh part of Ladakh. So, these are the images captured by some sensors mounted on a suitable platform the sensors are basically the cameras which can capture the picture actually. So, the technology is the definition is very simple like information gathered by instruments carrying on suitable platforms the information is used to study targets of interest on the air surface. So, this is the definition of the information in the technology. Now, basically the process if you have to identify A is a source of energy it says the electromagnetic radiation B is a process it interacts with the atmosphere we know that when the sun rays interact the atmosphere some will be scattered away reflected back and some gets penetrate through the atmosphere the atmosphere particles then it is the target and it interacts with the target in 3 ways some of these radiation will be absorbed some of it will be emission and the transmission. So, some will be emitted some will be transmitted some of this energy will be absorbed. So, they are reflected on the energy which will be emitted from the surface it will be reflected back to the atmosphere will be captured by the which is the particular instrument mounted on a particular platform. So, here a platform is a satellite platform. So, it is a satellite as we satellite vehicle where the sensor is mounted. So, it received their particular reflected back the radiation and we will get the data which will be transmitted back to your E which is the receiver stations. So, they receive the data regarding those you know captured objects may be in a numerical data or you know in a film data kind of a thing. So, they have captured it and then we go for interpretation and analysis and then application part. So, interpretation and analysis will be those visual images which I have already shown these are your interpreted or analyzed images. Then you can go for application like a change detection what was there before tsunami and after tsunami before the attack after the attack before the industrialization after the industrialization. So, these are going to be your application part. So, in brief this is the overall process of the remote sensing. Now, as I have been continuously referring the suitable platform suitable platform suitable platform what are these platforms basically there are three platforms four. First is your space board platforms which are the satellite which is located more than twenty thousand or you know thousand kilometers away from us. Next is your airborne platform that means the photographs they can buy the aircraft may be three thousand four thousand feet away from us aircraft this is a space board airborne platform and a ground based vehicle. The ground based vehicle that means the cameras mounted on a particular vehicle this is very useful in advanced countries that they mount this camera on the vehicles and they run the vehicles through the downtown areas of the cities because due to that in the downtown areas due to these high rise skyscrapers and buildings it obstructed other objects. So, remote sensing technology viewing from the space that the eye on the space is not sufficient sometimes. So, you use the ground based vehicle to capture the images the roads and the surrounding images in the urban areas this is very useful and the also sonar the sea vessels. So, now you can detect we know that in the ground vessels they detect these objects and in some sound waves right. So, this is a kind of a remote sensing. So, basically broadly there are three and for your sea vessels like inside water we can also have the remote sensing technology like sonar. Now, this used for a range of targets like the rock types, land use, forest, water. So, we know that as we are capturing the picture of the art we are going to get information the images of all these objects which are which are there present on the surface of the art. So, remote sensing comprises of two things basically one is your data acquisition and data analysis. So, data acquisition part is that this site where you acquire the sense data in a form of a digital format and you then you interpret and it send it for analysis. So, after analysis it helps us in our decision support system. So, data acquisition and data analysis these are two basic you know things in case of your remote sensing technology. Now, let us take the example of our camera. What type of cameras we have because the sensors are basically cameras which can capture the reflected back energy. So, light is pointing on you it is coming back same technology like our eyes it is coming back to me and my this lens you know it is capturing this and I have a film kind of a retina which is film there in case of your camera. So, it captures that particular reflected back light same technology, but here in case of your sensors we have two types of sensors in case of remote sensing. Similarly, like we have in our camera technology like if you have bright sunlight you do not use the flash why this you got to use the flash when it is done why because we need the light to fall on that particular object and to come back. So, whenever you that the kind of camera or the sensors which can use or which can operate without light these are known as a passive sensors which can only operate in case of light which has its own light active and which can operate sorry which can operate with its own light these are the passive. See this is active it has its own light. So, rubber, leader, radiation detection and ranging light detection and ranging sound detection and ranging then light amplified and stimulated energy radiation laser these are all kind of active sensors they send their own energy and capture the reflected back energy. So, they can operate without sun that means without the EMR of the sun electromagnetic radiation because they have their own energy to send and to capture like the thermal infrared scanner detected the heat given by a target at any point of time you can capture solar, rubber, x-ray, laser all are active remote sensing because they have their own source of light energy. For example, the flash you are using in your normal camera this is active. Now, this is passive. This is passive why because it can only operate in presence of light sunlight EMR electromagnetic radiation. So, these are the passive sensors. So, we also have both passive and active sensors. This is a normal technology as I have already mentioned the photographs are taken by the cameras using film which is sensitive to different wavelength of radiation at different wavelength it captures a particular object. So, the blue object will appear as blue, green will appear as green because they are reflecting their energy in the green band or blue band kind of a thing that is why we a black body completely absorb everything that is why it is black we know this technology right. So, similar very simple technology. Now, this is that particular you know tracking. So, the scenes are specific because you see the camera has its own coverage like if you try to click a picture using your normal camera you can only capture a certain amount of you know area of the landscape right you cannot cover the entire landscape. So, similarly these sensors they also have their own field of views that means the dimension up to which it can it is going to capture the information and to have a continuous data you need this track. So, they sense everything along this track. So, this track seems required line by line. So, you will have this path and rows. So, the path will be that particular track through which the sensor will move and the rows will be in that specific scenes. So, the path and rows will come you know constitutes your entire you know scene right it will come suppose you need to capture the image of Kohari satellite image of Kohari. Now, in some satellites you may require two three satellite images to capture the entire Kohari. So, there will be some path and rows along which actually the satellites scan this particular landscape. So, with this type of satellites we have like India's launches GSLB, PSLB GSLB are the geostationary satellites. PSLBs are the polar orbiting satellites. What is the difference between geostationary and polar orbiting? Geostationary satellites are basically the communication satellites. They remain fixed on a particular location on the space. Why? Suppose the communication satellite for India or broadcasting satellite for India you want also for the weather satellites which is you know providing as a weather information. The weather satellites you need to remain that satellite over a specific point at all the time. So, that you can get the weather data. So, these are the geostationary satellites they are set in their orbit in the same speed of rotating the earth surface. So, earth rotates that speed is same. So, they remain you know static on a particular point in the space and it is continuously capturing the data. But in case of our remote sensing most of the remote sensing satellites are polar orbiting satellites. So, this is a near polar orbit, near polar orbit. So, some of them have a repeat cycle of 4 days, 3 days same with the GPS. Do you remember? Twice they passes through a specific point. So, these are near polar orbits. So, they have a repeat time like 3 days after 3 days or 10 days the same satellite will pass through India or a specific point. Suppose the Guwahati ok. So, if we have a satellite with past time of 14 days. So, in every month that particular satellite is going to capture a picture of Guwahati twice because a 14 days is a time period. Repeat time repeat cycle. So, this is a near polar orbit. So, most of our remote sensing Indian remote sensing satellites are polar orbiting satellites and the communication satellites are geostationary satellites. So, this ESLV and PSLV ok launching vehicles are different ok. This is the swath that particular track through which our sensor will sense the area. It is known as a swath ok for a particular satellite. This is swath. These are some standard terms ok I am giving you. This is the least for high resolution multispectral image of Mumbai. This is least for Indian remote sensing satellite least for. So, it is least for is the sensor ok. So, which is having almost 5 meter resolution. 5 meter resolution that means it can detect an object of 5 meter dimension. Below there will be diluted. You will not be able to identify. So, anything above 5 meter you will be able to identify. 5 meter dimension. So, now you can see we are being able to you know locate the railway lines and you know all these. These four. The stadiums, roads, railways, but the buildings are not busy ok. We have a bright color for the buildings ok. The rates are of vegetations. Basically this is a false color where we assign rate to the vegetation. So, the vegetation appears as rate in a false color. Have you ever experienced the Google art? Please go through it Google art ok. So, there you will see that true color ok. So, if you compare the two color of this part of Mumbai the beach again zoo in Google art and in this image then you will understand. In Google art the vegetation appears as a green ok, but here the vegetation appears as a red because we assign red color to vegetation ok. So, this is a false color. These four high resolution multispectral enemies some of the buildings are now also busy ok. This is a particular technology where we can identify the objects and we can interpret it. Any changes we can interpret. Suppose the assign in the red color is actually helping us to identify the vegetation very easily right. So, that any changes to the vegetation covered can be identified ok. Similarly the buildings and other objects. Let me see in this particular image we have a different tone of red. You see this red and this red both are different ok. Now, this part of the I know this is settlement. This part of the settlement and this part of the settlement they are different. Can you see the color? Color is different ok. So, this is the the texture is different the color is different right. So, suppose we are not familiar with that particular area. It is not known to us we have never been to that particular area. We are trying to understand we are trying to interpret the area using this particular image. Now, there are some elements which actually help us to identify the objects in remote sensing and this is known as a visual interpretation of satellite image. Now, for a visual interpretation if you would like to interpret this particular image ok. I know that you have never been to this particular area ok, but you would like to identify the objects. Now, you have to rely on some of the basic elements of visual image interpretation. Now, what are these basic elements of the visual image interpretation? Tone, shape, size, pattern, texture, shadow and association. I am going to explain them one by one. Now, the tonal variation see the tonal variation here. So, this is an active volcano which is located which is covered by a quick bird image in 2002. Quick bird is a very high resolution image ok, high resolution satellite image. Now, here you will be able to see the tonal difference. So, this is a hill basically it is an active volcano ok. So, here is a theater ok, the mouth of the volcano. So, this is a what is this? Not snow, not clouds. No, coming out of there ok. I know this is a vegetation. So, can you see the difference between the tones ok. So, this is not exactly ray, but this ray is actually faded and slowly slowly. So, that means towards the top very less vegetation. These are almost rocks, rocks. So, these are the rocks ok. From downwards you can see the vegetation. So, this is a tonal difference ok. So, the tonals refer to the color. So, that color difference enables us to identify this particular object ok. How do I know that this is a volcano with the locational influence? I know that in this particular area of the earth surface ray is volcano active. So, it captures. So, I know that this is a volcano. Now, see it is very important. See for instance suppose you have two planes. How it helps actually? Now, this example is from I guess this is from one of the airports. What is suppose the sea? Two buildings. See I will be able to identify looking at the sea. So, there is a rope. This is one building. This is one building and there is one building like this. And no sorry. So, there is another building of this size. These are the seas. Now, in rural areas or in some of the urban areas also semi-urban areas, some urban areas if I see this kind of a sea then I will immediately understand that this must be a school. If I see in an urban area this kind of a sea I must understand that this is going to be a commercial building or a huge administrative building because it is a safe of a pentagon which is quite unusual for residential complexes. So, in that manner safe help us to identify the opposites. See looking at the safe I can clearly identify that this is going to be a pyramid. So, this is a great pyramid of design. Captured by Louis Bird in 2002. Louis Bird is a particular image from US. Now size. Again the size. For instance suppose you are in a zone. You know that this zone is comprises of commercial, residential and industrial area. Now there will be n number of buildings you will visualize. You will be able to see using the satellite image. Now the size of the buildings will tell that this must be the commercial or industrial area. Size and shape will help you. Like big, big, you know kind of a suppose if you have these kind of elongated, elongated safe buildings. So, they must be warehouses. Immediately you will be able to identify okay this is the industrial area. Suppose you have big, big buildings like this. I mean safe like this. You will be able to know okay this must be a commercial area. And small, small, square safe residential units or the building units, this must be a residential area. See, this is the Canada. Okay, Ontario, Canada in 2000. Somehow you will be able to easily identify. See, these are the residential units. Okay, this must be a commercial unit. The tower. Okay, so this is the railway line. Okay, the big buildings, commercial buildings, the high-rise twin towers. Yeah, building. It is easier here because it is a very high resolution image. But with a low resolution also we will be able to identify with the hip of size, shape, tone and etc. Now, pattern. Pattern is also very important. Can you identify this? Red, red circles. Okay, so this is where the sprinkler irrigation system. So, here the vegetation is present in these areas. There is no vegetation. Okay, so these are the vegetation. So, this pattern tells us that okay this is a part of a some kind of a nursery or garden kind of a thing where they have a sprinkler irrigation system. Okay, this pattern is also important in our part of the world to identify and distinguish between tea gardens, forest areas and the agricultural fields. Okay, see forest areas, what will be the difference between the forest area and the agricultural fields. If you go to see this in the, suppose if you are in Google Earth, you go and see the part of Tinsutia or Deeprugam. Okay, so you will see the combination of forest, tea garden and agricultural area. Now, forest you will be easily able to identify because of the texture. Okay, the coarse texture because of tall trees. But your tea gardens and your agricultural fields will have the same kind of a same, square same, man-made same. Okay, but the tea gardens, again the texture will be different from the agricultural fields. Agricultural fields will have a smooth texture of vegetation whereas the tea leaves in case of the tea leaves and due to the presence of the sand or giving trees inside the tea gardens, you will have a coarse texture. Okay, so then you will be able to identify. Both are man-made, but these must be an agricultural field and this is a tea garden. Okay, you try to see. Okay, in a Google Earth, you try to see the tonal variation, the same variation in case of our tea gardens and the agricultural fields. So, this is better. Again we know that this is a post. Okay, so this is a part of post in Australia, bull post of Australia. And this again iconosemis. Texture, as I have already mentioned, texture. Forest canopy, light texture and other canopies are going to be smooth texture, rough and smooth. Okay, so this is a smooth texture. I know that this is a man-made. This is not natural. Okay, these are the gardens, all sorts, where we have a sprinkler irrigation system. But for here, I know that these are the forests. Can you see the texture? Garden. Okay, see the texture of the nearby forest. Same green, but the texture is different. Okay, and in case of the, you know, the same pattern. Okay, so this is a man-made feature. Clearly visible, squared shape. Okay, so this is a forest. There is no same. And texture and shape, it will help us to identify, to distinguish between two types of green. Okay, vegetation. This is sandow. This is a sandow from the cloud. Okay, so the sandow is also helpful in interpreting. It provides an idea of the relative height of the feature. So, these are the cloud covers here. So, this is a part of your Indonesian article, Fiji article. This is a part of Fiji article. Can you see that here, in this image, you will be able to clearly see. See the sandow. We know this particular building and this tower, they are adjacent to each other. See the sandow part of this building and the sandow part of this tower. We know that this tower must be very taller. This tower is taller than this building. Why? Because it has a long shadow. Can you see? Though they are almost closer to each other. Okay, there is a long shadow. In that way, actually, the sandow helps us. But in case of satellite image, sometimes it is not good to have shadows. Because the shadows offset the information. We do not like to have satellite image with a huge cloud cover. The cloud cover, the sandow and cloud will obstruct the object below. So, we will not be able to use that particular image. So, the cloud and cloud sandow, cloud cover is not acceptable or desirable in case of your remote sensing technology. But definitely sandow has its own merit. Because with the help of sandow, we will be able to get some idea about the height, relative height of the object. Relative height. Not the absolute height. Relative height of the object. This is not a big funding. This is not a big funding. See the cloud cover. Same image. This is Simla. This is a very close to resolution, 24 meter resolution. So, that part of Simla is not visible. Can you see? These are the hillsides. The sandows because of the hills. Tonel variation here. The bright covers, bright things here. So, this is the second one. These are the vegetations. Vegetations. Lace vegetation. This is the sandow. And the hillside effect is showing that this is a particular satellite image of a helitarian. The sandows stands out as an image of a helitarian. And the tonel variation, color variation, we can identify where the settlement is located. Last. Association. Association is very important. It helps us to identify association. For instance, commercial properties, industrial properties, industrial locations will be close to the highways. Right? Radio alliance. Connecting the industrial zones. So, if there is an industrial zone and you are seeing some big, big shape buildings or something like that, then it will be easily able to identify that it must be an industrial zone. Some big, big high rise, kind of a big shapes along with a major highway. These must be a commercial complex or something like that. So, this is the settlement area. These are the commercial areas. Can you see the pattern of the buildings? Here there is no pattern. We can see some patterns here. This is a major highway. So, you see that we can easily identify this must be a commercial area. Yes, it is in Mumbai. This is a commercial area. These are the residency areas. This association also helps us to identify the options. Railways, lines and road lines. See the association. Side and location. I know this is not cloud cover. This is snow cover. Why? Because I know the location. This is a picture of Mount Everest, by Aconos, 4 meter resolution. So, this is not clouds. This is snow. So, location also gives us some knowledge. If I know the location like that volcano at Deepakamal because I know the location. That is why I will be able to identify that particular object when easy. That this is the smoke coming out of the acne volcano. This is snow on the high mountain. So, like that. Last slide. It is very helpful. The remote sensing technology is very helpful to identify the changes detection. So, this is the Agence Olympic Sports Complex. Captured by Aconos. 14 June 2003, 24 July 2004, 15 March 2001. So, this is a starting point. 2001, 2003 and 2004 July. It helps Olympic location. Let me see the changes. The old structures, ok, been completely renovated to a new structure. This kind of change detection. So, there are n number of uses of this remote sensing technology. It provides the basic data for our decision support system to be used in the GIS system. We can do the you know inventory resource inventory mapping, land use land cover chains, ok, flood and other, you know, the damage by the flood and other atmospheric, you know, natural hazards and like that. So, in every aspect of our analysis, our decision making, the remote sensing technology supports, ok. They provide the basic data which is required to work on. So, that is why this remote sensing technology is very useful. Thank you.