 Hello everyone, welcome to NPTEL course on remote sensing and GIS for rural development. This is week 7, lecture 3. In this week, we have been looking at Google Earth Pro for accessing data and information quickly, which can aid in creating a database for rural development. In the last examples, we have looked over the lectures of Google Earth Pro's toolbox and what can be achieved. We also noted that there are some advanced levels which a lot of students do spend time on, for example, Google Mars and Google Moon, Sky, etc., but we will focus on Google Earth. A lot of data is present and we looked at some methods to limit the bandwidth and memory of running Google Earth Pro. In today's class, we will look at how one can extract information from Google Earth Pro using ground control points. So in this week 6 and 7, we have been looking at tertiary or proxy data that can support our analysis for rural development. In one such case, we looked at a scanned toposheet, a scanned map from survey of India. We noticed that there is a lot of information hidden in the paper maps, but unless it is put on a GIS platform, we cannot quickly take the data out. And one way we looked at it is by using the lat-longs provided in the map as ground control points or GCPs. So in the geo-referencing tool, there is a lot of ground control points we need to give, at least 6 for the nearest-neighbour method that we used or polynomial 2 method. We will say we need 6 points, but you get an image from aerial photography or a paper map that does not have this information. Then what do you do? Let us look at some examples. So this is a beautiful aerial imagery taken from Maxwell Technologies. I am making a case here saying that this map is on the Ilahan Ka Lake, but there is no other information on it. For example, there is no lat-longs, date, time of flight or the other accessories that you can take for using as ground control points. This is similar to a lot of paper maps. You can have a paper map like this where only part of the map is available. You do not have the boundaries where you have the GCPs that can be extracted. Or the grids are there, but there is no data on the grids. Let me zoom in and show you. So you can see that there is no numbers or any data information that can be taken out. But there is this Ilahan Ka Lake and other data that can be identified, names, etc. So the idea here is to use Google Earth in parallel to look at similar imagery and then extract the data out. Let us take a case study of this image. This is what I will take in a particular date. So let us open our Google Earth probe and we can look at what are the points that can help in assessing these boundaries. So let me open and share the Google Earth probe. Yes. So now what you could see here is an image which was very similar to our image, right, to the image that we had on the PowerPoint. What we can access is, for example, you can look at some control points like these small circles. I hope you remember that these two circles were present in the imagery also, right. So I am going to share just in between these two screens so that we can toggle back and forth and see the image. So here we did, we did see this part, right. So you do have these two circles and this circle is there. So kind of these are like aeration chambers or valves to keep aeration in the lake or some drainage lake so that if the lake goes over a particular volume, it will be drained. So some structure, let us keep it as some structure and it is circular and there is a center in the circle, right. So that point is enough for taking one control point. So this is how one can go ahead and collect ground control points. Let us take two points just for example, okay. So as I said, this is the circle and you can take a point on the center of the circle and you collect the latlong. So this latlong is where you can enter in the GCP latlong, correct, the ground control points in the georeferential tool, you can use this and put control points. Similarly, let us take another point. You can take another point here because that is also in the image. You could take this ground. You could see there was a ground that was taken or yeah, airport, right. So this is a flight deck. So pathway, runway for the flight. You can take these two, one of these two chambers, the center of the chamber because airports do not change much, right. So all these, the planes, you can see here the planes, all these are parked, looks like a air force base because commercial means it will be too much longer or a bit bigger than this one, right. So you have these two hangers also. You can take those locations. For example, you can see either you can put your pointer here and read it at the bottom of the screen. You can see at the bottom of the screen, there is the latlongs if I put the marker here or just put the marker on top and then same way you have to put the marker on the image, okay. When you do the GCP points, you remember in the GCP points, you can zoom in and put the points, okay. So you could see the lake and on top of the lake there are some areas of interest. The airport is around here somewhere, right. So you could extract those points clearly from the maps, right. So these parts have been changed. So we don't know much about maybe we can use a different area, image, let it load and then we will find. So you can keep on updating the image to find the correct control points and then extract those control points. So you can see here something is developing or maybe we will just use the latest one. Oh yeah. So there is the ground. So maybe the ground was being built, initially there was no ground, right. So they're trying to build the ground, there's nothing here but then the recent years, 2022 there's two grounds, right. So it looks like one track and field and then a cricket ground. So and a football ground also. So you can put a pointer at the center of the ground or the center of the cricket or football you can see here, there is a circle and a center. So you can just put it, this is easier to mark, you can put it on the center and then take the lateral. So by doing this, you can extract control points into your DCP, there's your reference it and then you can reference the image, which we have in the Google document. So this is it. Using Google Earth Pro, we have shown that we can extract information. First thing, the first step is to focus on the image you have. So you can put a point, let's see, I'm going to put some points here. So we said that this is one point, this is one point. And then we saw a cricket ground, a football ground. In the center of football ground we put a point. You'll have to zoom in. So when you do the georeferencing, you know you'll zoom in and then take the values. So you go back and forth in Google Earth and then you collect the DCP point latlons, put it here and then you extract it. The same thing here, you could look at the center of the lake or the center of the structure. So the center of the structure does have a point. So this one, you could see here, there is a point. I'll show you. Okay. In the Google Earth, if you go back to Google Earth, we said this structure, right, there you are. So you see this semicircle and then the center of the circle has a point. So here we can take a latlong and that latlong will coincide with the latlong here and then we take the DCP points. This is, it's not as accurate as taking values from a map, but if you triangulate the four or six points, take as much points as you can, let's say six eight points, then while triangulating between the points, there will be some, there will be some assessments and the accuracy will be improved because of the model, because it's interpolating between the data. So let's move on now. We will go to the QGIS point. So this is by shifting back and forth between the two softwares, one is Google Earth Pro and then QGIS. However, there are multiple ways of bringing a map background into QGIS. We will look at some, but before that, I would like to introduce a concept of plugins. So plugins are a toolbox, a set of toolboxes that have already been created by users, volunteers, and you can run it efficiently or effectively with simple inputs. Say for example, you need to add A plus B plus C is equals to D. Instead of putting A, B, C separately and merging them into one draster, you can open this tool and just quickly add it. So it's basically a GUI, a graphical user interface with all the tools in the background. So let me introduce the concept of plugins from where we will jump into a couple of plugins which are very important for bringing the background image. So in the user guide, you will find that the plugin database is there for learning and understanding the plugins. The link is given up here, so let me quickly open it and I'm sharing my screen now. So in this plugin, what do you see is that in a tutorial it says about the plugin tab, the core and external plugins, core needs some tool sets, toolboxes that are always in QGIS. You will always be using it. They have turned in one or two languages, either C++ or Python. The first aid is in the Python programming language and it is a core development team that has created the core plugins. If you click the core plugins, you will find what the core plugins are. It's basically database manager, graphs, offline tools, processing, SAGA, topology, checker, etc. Then as I said, you have an option of including or using the tools that have been created by volunteers and users just like you and me. So they would have stored it in a GitHub or some other cloud space and then merged it with the QGIS catalog. And all you can do is if you like the tool or if you've heard good things about the tool, you can import it into your QGIS and run it. So that's what we'll be doing today. We'll be looking at a particular QGIS plugin and then accessing the benefits of this plugin by using a database. So there is a settings tab. There is a updated tab to show how much are updated. And then all tab, we'll go through all this in a quick example mode. So let me share my QGIS. While my QGIS is opening, I'd also like to mention to you that some of these plugins work and some they don't work because they are created for a particular purpose for a particular region and it requires you to have login to some systems, for example, an account. So you'll have to read more about it. And sometimes they have bugs. So that bugs means there's not viruses, but it doesn't work after some time or it runs in a loop. And that is why they are not part of the core plugs, core tools. These are good tools, but they're not core. So I would recommend you to read about them. Look at them in the literature. They have been used widely. And if so, you can use it for understanding the usefulness of these tools. So let me open the QGIS or share my QGIS page. And we will open a new template and go to Plugin. So first, if I click Plugin, I already have some plugins. For example, Google Earth Engine Plugin and Jaltol Plugin. So first, I want to teach you about the Python console. So this is where you can run a code from Python about a tool and execute it. You can do an editor, click on the editing tool and then you can edit the tool, copy the code, paste it, run it. And then it comes to here and then you run it. So for now, we are not going to use the Python. It's kind of advanced. So we'll be using the manage and install plugins. Once you click it, you'll find this opening out. It's called fetching repositories or database of tools. As I said, there is one cloud space where all the tools are being linked to. And each time you open QGIS and open this managed toolbox, it will run and bring it. Only when you're opening it new. For example, if I close it and then run it again, it won't take that much time. Okay, it pops up. It doesn't wait for the repository because you just updated it. But when you close the QGIS and then reopen it again, then it will check for new updates and then link it. So what it first goes is into the install box. So how many plugins have I already installed? Looks like I have a couple of toolboxes installed or plugins installed. These are kind of apps in terms of your mobile phone and apps Play Store. So this is your Play Store for downloading new apps. And as apps sometimes work, sometimes need updates, the same thing goes for plugins. This is one of the core. So every phone has core apps. Let's say my camera is a core app. My messaging, my phone call is a core app. You will not throw it out and you cannot delete it. So something like that, you cannot delete some of these apps. For example, I don't want to or I cannot delete this toolbox or this add new toolbox. You cannot delete it. You can remove it from the toolbar so that you can have more space, but you cannot delete deleted. Toolbars are all with inside the toolbox. These are core tools. So it will always be there. So in the plugins, manage and install plugins that are core, which are not going to be visible here. These are only additional plugins. So apps are additional. And sometimes you will install, reinstall. All this happens in this. So this is like your settings for your QGIS app. So now what you can do is you can see like how many I already have. I know some of them are not working. So I would not put a tick box on them because it's taking my space on the top or just taking slow because it takes time to install. Not install is what are the remaining plugins that are not installed. As I said, these plugins get updated regularly. So let's look at how many plugins are there. There's a lot. And it depends on what are you going to use it for and different languages and setting. We'll go through some of these plugins to just see what they are and how they are done. There's always like a stable version. Release some PDFs about where you can find the reports. How many people have downloaded it? So 10,000 downloads, eight votes have been given. Same like a shopping app. If you go to an app, you'll see how many people have downloaded it. Some reviews here. You don't see the reviews. You can also see the star rating, etc. So this is upgradable. So within my apps or plugins that I already have, there are some that can be upgraded. So let's upgrade the plugin. So once you upgrade it, it says downloading the data to upgrade and then it's upgraded. That's it. It's done. So now that part is gone. So then Google Earth Engine, let me upgrade that plugin also. And it says there's a newer version. So it's getting updated, which is good. And then you can upgrade. You can also uninstall and reinstall a new plugin. Okay. It says not responding. Maybe some there's some bug and or maybe they don't have the updated version. So let it run for some time. But meantime, let me open another QGIS also. So the best way is to always check for updates online or it may pop up saying that there is an update when we ran the software. And those kind of updates we can use for the plugins. Okay. So now moving on, we will, okay. So let me reshare the screen again. Okay. For some reason it had closed, but it's okay. Now we have a new template, new plugin, go to manage. So you see all my other tools have been gone because I had updated them and you can easily use them. Then there's not install install from zip. If you want to install a zip location and settings, check updates on startup. If you want to check updates on startup every time, don't do it because it'll just take more time. If you want a particular update, go to the app, read it and then update it. If you do this, every time you start QGIS, it will check for updates. Okay. And then show experimental plugins, deprecated plugins don't do only if you need, you can do otherwise don't do it. And this is a default plugin repository or the data bank of all the plugins where when you want to install it, it goes there. Suppose this is not readable, you have to edit it or reload the repository. Okay. So now I come to all and these are all the plugins that are available. Let's say clip multiple layers. It says first, it's very, very simple to read. So it's just clip all display layers, rasters and letters with a polygon layer selected. For example, this is like a toolbox. Okay. So let me draw and show you what it means so that you can understand more about a plugin. Suppose you have one layer and then you have a tool to clip. So the output would be the same with one layer. So this is one layer. You clip it into this, right? You clip it using the clip tool and then this shape file, you get this inside this one. Okay. But now if you have multiple layers, if you have multiple layers, let's say one to N. So what happens is when you clip this, using this clip multiple layers, you will get one to N multiple layers within a single button. So you don't have to do it again and again and again. Just select all the layers, select one clip mask, clip tool, you select and click, it will automatically clip everything. You don't have to, let's say you have land boundary, water boundary, soil type, agricultural type, everything has different layers, five layers. All these five layers will be totally clipped into one parcel by just this toolbox. So it's a very, very useful toolbox. They have given an icon also here which kind of relates to what the tool is about. So now let's go into what we came here for. I'll show you that screen. So that we can see in the presentation what we are going to look at. We are going to use the base maps. So base map is, suppose you have data, behind the data, there is some base map that is similar to Google Earth Pro maps. In the Google Earth Pro, you have base maps loaded and that is why you can easily quickly take out information. So that is what we are going to use now. Right now, until date, we have been only using the boundary of India as the base map. Now we are going to use some data. So what does the base map help in? It avoids accuracy, because if you say there is a land and you cut the land from multiple layers and bring it into the QGIS map, unless you have a base map to authenticate that yes, both the layers are in the same location, you are correct, otherwise you are wrong. For example, you clipped Karnataka boundary and then when you bring it into the India boundary, if the Karnataka boundary is going into the ocean a little bit, it is wrong. So you will have to make sure that the boundaries are correct. So that is the age accuracy. It helps in importing data. So from the base map and the shape file you have, you can extract data. So the base map might be the global coverage. You do not need the global data, but only for your area, you can zoom in and take the data out. All the attributes can be collected. Suppose your data has only state names, country name and then some major roads, but your base map has the names in different languages. Suppose Hindi, Tamil and then you can take the name out of Tamil and put it into the database. Then you can also see, can be used for data mining. This is where some tricky, tricky things that are very sensitive may not be put on the big open source maps, but in the paper maps and base maps, they might be available. Location of schools, Anganwadi's, these maps on the paper map can be used as a base map. Then from your data, you can add into the database. Of these tools, one widely used tool is called the quick map service. Let me open the QGIS and let us install it like. What we will do is we will install the QGIS plugin, show you how to install it and then run it. Now you can see it. So go to plugin, manage and install plugins. Here in the search box, you can type quick map services. Let's read through it. It's easy to add base map and geo services, easy to use list of services and search for finding database, datasets, base maps, and then you can contribute new services also here, which means you can also give some links to new data. For example, install data is there. Maybe it is not linked to this database and you can link it just by writing some codes. You can also give a feedback to this contact list. So 918 votes, really high votes, more than 4 million downloads, which is pretty big and a lot of updates have been done. So very recently, we have done an update also, just two weeks before. So let's install the plugin. It's very simple to install. When you click install, it installs. There's no payment. There's no membership. So it's all free open source. That is the beauty of using QGIS. It gets installed. So now if you see, all these have been installed. And it says the install plugin goes off. Now it says reinstall or uninstall. Uninstall is if you want to uninstall the plugin. Reinstall is sometimes when it installs maybe some errors, script and your memory did not work properly. And so it didn't open properly. So you can actually reinstall it if you need. But let's go to install services and only one tool is there. So we can close. Let's see if it has come up. Plugin. And then in the manage again, you open. Yes, it's installed. Very good. And the symbol is there. So the symbol is very different. So this is the symbol for quick map service. Some plugins you will see them open out here, but some others will occupy the toolbar. So you should know where and how the toolbar looks like. For example, if you're going to manage tool, and then if you see this logo, if you see this icon, that is what the icon is going to be. So now you can see this icon right here. I'm putting it side by side so you can see that it has populated. Okay, so let's uninstall the plugin. Yes, and you'll see that these will manage. So now it's gone. Now I'm going to install the plugin and then it has come up. Okay, so I'm going to close it. Okay, so now to start up, let's fire up a database. A vector file. Let's say I would like to see the India file shape file. So I'm going to say India shape file open. And now it has been added. So to this we're going to add the base file. Okay, base maps. So these are quick map services meta search and search QMS. I'm going to do the quick map service. And then it asks me what base map you want. So if you remember while installing, it said that you can also install and give maps into the service. So if we are in advanced level and we know that the map is accurate, we can also install it into this package. For now we're not going to install. We are a user. We are not a contributor. We'll be a user. So let's say the NASA, you have earthquake hazard distribution or earthquake ground acceleration map or earthquake hazard distribution. These are the two data sets, base maps that are available from NASA. But OSM has OSM standard maps. So let me click OSM standard map. You will see that it has been populated in the layers list and in the behind also. So I'm going to make India a little bit just the outline. So go to properties. Simple fill. I want the fill color to be maybe red. And I say, okay. And the stroke or thickness could be one. Okay. I don't want fill just simple outline the black red. Okay. One millimeter thickness apply. Okay. So now you could see the boundary and behind that you could see the values. Okay. So this is the base map, which has been generated from OSM open street maps. So you can see that a lot of roads streets are coming up basically from the open street map database. This was not available for us. So now we can draw and extract out like we did in the layer analysis. Like for example, here we used and say shape file and then we traced along this and said this is a road. I can trace along this and say this is a river, et cetera. Okay. So this is one base map that we can use also to see if my boundaries are correct. Okay. So you can see that here there's an OSM standard map. Now you can click the second part, which is a search. If you click the search, then you can see that some data sets are coming up and you could see that you can see valid and then everything can come up or just a valid once filter by extent. It's going to filter like within this database. How many data sets are coming? Okay. So you have someone populating from a magic code or DE and then some maps which are about Adams Bridge. So Adams Bridge is here. This is called Adams Bridge by some people. So let's say I'm adding it. If you add it again, it comes up here. Okay. I'm going to take these other layers out. And as I said, the Adams Bridge is between Sri Lanka and Tamil Nadu. Tamil Nadu. So let's go to Tamil Nadu and then see how it looks like the zoom to layer. Okay. Maybe let us put this back. Okay. Okay. So I'm going to take the OSM off and then just keep the magic code, the Adams Bridge. So now you could see that the Danish code and Sri Lanka part is connected by the Adams Bridge or Ram Setu Palam Bridge. And then that has been done. So this is a database base map that can be added. You don't have to download it. All you did is just the plugin and then it came up. Right. So you can say Google with correct spellings. And then all the Google plugins will come up. It's searching, let it search for some time. See all. So initially you had only two, three, but now you could see how much more have come up. So you just have to search. There's many, many, many base map layers. So this is cloudless Sentinel-2 data. I'm going to add a Sentinel-2 data. You see. So without cloud cover. So it has picked a date where there is no cloud cover. And you can click on the details to find another screen as open. So let me share that screen. Okay. So it's opening up and saying that what it means. So you can see here. So this is what the link has been opening up when I click the QGIS map. So I click the details. Then it went to that. Okay. So that is one layer, which is very good. It happens throughout the world. It does have data. It has a large data set. So it is taking some time. See. And Sentinel is very, very high resolution. 10 meters in some locations. So you will see it. So this is the ES cloudless map. So when I click the details, it came to here. And you can see that what date the map was added. 2018. So when it was taken, the copyright extension. So this was the map that goes into the base map. So 2018 map has been updated. So May 16th was the map. Okay. So let's go back to the map. And then let's say glad forest year loss 2000 to 2021. So within the Indian boundary, if I'm going to add this base map, you're going to see where the forest loss has been high. Red color means forest loss. Okay. So this is normally the technology that is used. And you can see it from the details here. We use this one, right? 2000 to 2021. Let it open up while we are going back to this map. So now it has been generated. You can see a lot of forest loss here. And this also says data forest loss, earth engine partners 2013. The date has been done. 2020 last updated 2022. So, but the data is from 22,000 to 2021. Okay. And then it says, so basically this is the same map. This map, which has been the red color showing that there is loss of forest cover. So green means it's gaining. Red means it's losing. Okay. So here you can only see the loss because the term we are using is loss. Okay. And then if we don't need it, we can remove it. All these, as I said, we can move the layers and say, okay. So all these are Google. One thing that we can use is Google traffic, right? You don't see that as a map. Let us use it. So these are the high traffic regions and low traffic regions getting populated along the map. It will take some time because all throughout India, it may be looking at. And maybe it's not only populated along the major highways. So let's come down and see what else we can see that we can use Google. All these are Google. There's some Spanish data set extra. Let's see if there is some ISRO database. Yes. There is a boon ISRO database so we can add it. So instead of going to boon, taking the shapefile going to boon, we can quickly analyze it here. So you see there is a layer. I cannot be added to the map. There is some errors, some plugin extension may not have been there. So we can take it off. So these are the maps that we have used. Let's use one more. Night light. We don't have it. Grace is a groundwater satellite. We don't have it. So this is how you can search for some satellites and use it. Let's say NASA. Let's see what NASA has in terms of database for India. Plenty. Plenty of NASA. So there's fires in the past seven days. So if you're looking at stubble burning and fires, you can look at that hotspots, fires, aqua hotspots, global multi-resolution topography synthesis. A lot of these things are there. Let's say just add the aqua and then let me take off the traffic. And then we have to say, okay, then the red mark, I'll click, okay. Okay. So sometimes the data might not load because it is for pan world or it just takes a long time to load. Remember, this is a plugin that talks to the data source and brings the data source. So it may take some time for downloading the data. Okay. But I would like to finish with just the one data that we can use. And mostly it's Google Bing maps are there like Microsoft. Google is there. So let's just use a Google Landsat mosaic. Mosaic is a satellite that has been mosaic together to give the overall image. And there it is, beautiful Landsat mosaic is coming. So I'm going to remove the other layers just for memory. And you can see that beautifully the map is getting populated. Very, very high resolution imagery that you're looking at. What the color means, et cetera. You can collect, click on the details and go to the map and look at it. So this is about adding plugins and through plugins, a base map, a base map behind your map that helps you visualize your content. So my content is this India shape file, but I want to visualize other data with it. So what I do is I can add a base maps ready instead of going and downloading the data and putting it in. You can just click these buttons, add and then it quickly adds. For this, you need to install the plugin, which I showed in today's lecture. So if you go into the village areas with the village boundary, you can definitely see how the water bodies have been changing the green color reflecting the good crop growth and crop type. You can also see NDVI, which is a indicator of water and vegetation and then NDWI for water. So there's no results for that, but NDVI we do have some normalized indicators. Okay. So we will leave it here, but mostly the Google images are pretty good in terms of glad landsat mosaics. And then satellite hybrid models, maps, etc. I'll close here and continue the next class. I'll see you in the next class. Thank you.