Let's see how we can use the Trace Downstream analysis tool to map the course of the River Eden. The first thing we need to do is to find the source of the River Eden, which is just north of Aisgill in Cumbria. So if we search for that here by typing it into the search bar and it will take us to Aisgill, and if we zoom in a little bit, we can start seeing the River Eden, just north of Aisgill. What we need to do is to mark the source of the river by sticking a pin in it. So we click Add and Create sketch layer and you'll see that there are various options here. The one that we want is the simple vector point. So if we click that once to say that's what we want to do, then we're going to look for a place. Now I happen to know, it's quite near to this point here. It doesn't matter if you're a little bit further upstream or downstream, but if we put that just here, right in the middle of the river, of course, and then what we're going to do is name that so that we don't lose that point. So we're going to call that River Eden Source. Now don't click any more points on the map because it'll add other points. It's quite easy to do that unfortunately. But if we just click Layer, we should see the new point just here. It doesn't give it a name, so we can name it here as well by clicking the three dots then Rename and giving exactly the same name as we did before. We can now let the GIS work its magic by using the analysis tool Trace Downstream. So having clicked Analysis, we then click Tools and in the section Find locations, we click Trace Downstream. Next, in Input layer, click on River Eden source: Points. Then scroll down to Result layer. In Output layer name, type "River Eden Trace Downstream." Then click Run and the GIS will do its work. There's a lot of data to process here, so the Trace Downstream can take a little bit of time, but once it's traced it, it shows as a blue line which approximates to the course of the river. It's not exact, it's an approximation, but it's very useful to us, and to actually manually trace the stream would take hours and hours. So it's a very useful thing. If we pan out, we can see the whole course of the river from source to mouth. The mouth of the River Eden is near to Carlisle, and we can see how it's approximated to the meanders there. But that is fine for our purposes. We're then gonna save our map by clicking Save, Save as and in Title we type River Eden and then Save. At the moment, the basemap is the topographic basemap, but we can always change this to something else. So we go to the Basemap gallery and we can select perhaps Imagery, and we can see how the river corresponds with that. And that may or may not improve the visualisation. You can also change the colour of the layer if you want to. So the new layer is there. We can show its properties and then we can change its colour by clicking on Edit layer style. And perhaps me might want to choose a brighter blue. So we click on there and we can choose that colour blue there. That's a bit too dark. Some maybe we could choose something a bit brighter like that. And we click Done and Done again and save our work. Then we can hide the Layers panel in the dark toolbar and then pan out to see what the Trace Downstream work has achieved. We can see a very clear route of the river from source to mouth.