This is a GIS guide showing how to use remote sensing, historical aerial imagery and satellite imagery to visualise deforestation and some of its causes. To do this, we're going to use the Esri World Imagery Wayback app. It's an amazing collection of remote sensing imagery using both aerial and satellite images. It goes back to about 2014, and sometimes, as we're gonna find out, even further back than that. So if you go to the link provided, it should take you to this view here of Esri Wayback, and it's been set up with the Toggle Swipe Mode in place. And what this means is that you can move the slider in the middle to compare one image with another from different years. So you can use the panel on the left to select images that they have for this view, and similarly on the right. So typically you would choose an older image perhaps and put that on the left and a newer image and put it on the right. However, there is a word of caution with this, which is that the years and the dates they have here are not necessarily accurate. This is something I only discovered back myself recently. So although that says 2014, if you click on the image itself, it tells you that the photo was actually taken much earlier, the 15th of January, 1999. Similarly, on the right we see that this photo is listed as May, 2020, but if we click on the image, it tells us it was actually captured in 2019 on May the 15th. So not much before, but it's not exactly 2020. So we can use this tool to investigate the impact of semi-industrial or essentially illegal mining for gold, particularly in Peru. So this is Peru. If I just zoom out, you will see exactly where it is in the world. So we're in the province called Madre de Dios in Peru. You can see the area just there. And the dark green colour is of course the Amazon rainforest. And if we use the zoom control to look at a piece of the rainforest that's still intact, what we see the view from above, either aerial or satellite image, is we get this typical characteristic broccoli appearance of the rainforest. Now, if you pan and zoom around like that, you quite often end up getting a bit lost. So you can either go back to the original link to find the original view, or, gonna suggest you search for a place called Huepetuhe in Peru. And there's only one place that is named that as far as I can make out. So you should go straight to it. So if we click that, it takes us to that region, which is pretty much the area where we started, but zoomed out a little bit more. Now, this is just one region of Peru where gold mining takes place, and what we can see is just how vast this area is, roughly from there across to there, this area here would be larger than the whole of Greater London. So it's a very big area, probably about 50 miles across. So this is a major impact on the landscape and on the rainforest. And we can use the zoom controls to take a close look at the area. Do we see the canopy? Do we see that familiar broccoli effect? Instead of rainforest, we see a moonscape of gold prospecting pits. The processes for extracting the gold use a lot of water and chemicals such as sodium cyanide, and that flows or leeches into the landscape and is extremely harmful to wildlife and any humanity that happened to be in the area as well. So it's a rather troubling scene of widespread devastation with prospecting pits all over the place. I suggest you explore those. It's particularly clear in the more recent imagery, but if you zoom out, you can get some idea of the impact on the landscape by just going between the two dates. And if you're not quite sure of the dates, remember what I said earlier on, you can check by clicking on the image to see when the photograph is actually taken. So there are different ways of saving our work. If we just zoom to an area and we think that looks particularly interesting to compare, this is similar to the area we had a look at to start off with, we can see this devastation to the rainforest by the gold mining in that area. So what we can do is you can save the link to that by copying the link here where it's got a link symbol, and there is another way which is to go to the Toggle Animation Mode. So if you click that, we'll see what happens. What it's doing is it's offering you an animation to show all the images from all the years they have, but that can sometimes, for reasons that we explained earlier on, can be a little bit misleading. It's quite useful. You can see what's going on there. But perhaps what you can do is just to choose just two of the images. So I'm going to untick all the years except the years we were looking at. So I'm unticking pretty much everything, except I'm gonna choose the one from 1999, even though it says 2014, and the one that was from 2019, even though it says 2020. So if we do that, we just get a comparison of two images. But it's quite flickery. So what we can do is change the animation speed down to the lowest possible, and then it's a little bit less flickery and easier to look at. Then what you can do is download your animation, and you can choose the dimensions of it. Do you want a horizontal one or do you want a square one or a vertical one? It's got different dimensions there. So you click any of those ones to download your image. So perhaps we're gonna choose the high definition horizontal one, and it's creating the MP4. And when that's happened, we can download it to our device. And it might be a good idea to give it a more meaningful name. So in this case, we call it Huepetuhe, Peru Deforestation. And our download has been successful.