 Hello, and welcome to video five of the DHIS2 GIS Academy. In this video, we'll be looking at finding population living around health facilities. Firstly, we'll re-project our data sets, and then we'll move on to create five-kilometer buffers around our downloaded health facilities. And then lastly, we'll calculate the population living within those buffer zones. The first thing we need to do is ensure QGIS is open, and within QGIS we have our population data and health facility data loaded. For anyone following along with the Sierra Leone data set, you should expect to see something similar to this on your screen. We firstly need to make sure our data is in the correct projection for analysing data using buffer zones. To do this, we need to project the data for Sierra Leone to UTM Zone 29 North. To do this, we go to right-click on our data set, click Export, Save Features. We need to change this to GeoJSON. We need to set our file name and save it within our local disk, DHIS2 underscore training. And here I'm going to click on DAMA-FACILITIES, and I'm going to change the name here to include UTM 29 North. This way, when I'm looking at my files at a later date, I can differentiate this file from the reprojected file here, and I'll press Save. Under the CRS, as you can see, I can select EPSG 32629, which is WGS84 UTM Zone 29 North. So I'll select this and press OK. As you can see, this has reprojected the data set and saved it in a new layer. We can then change the symbology again quickly by double-tapping and changing the marker within the symbology section. We need to do this again for our population data. So if we right-click on our population data, go to Export, Save As. This time, we want to save it as a geative file, and if we press the Browse button, we can then save this under the same file name. But again, adding our relative coordinate system code on the end. Again, I'm going to change the CRS, but this time I'm going to use the CRS selector. And this shows you the different coordinate reference system you can use, and you're able to search for your UTM Zone or your correct coordinate system in the search bar here, and this will filter the coordinate systems available to you based on your search. So the reason why I'm using UTM Zone 29 is that this allows me to work in meters, and therefore I'll be able to produce a buffer zone of 5km. So if we press OK, and then OK again, you can see that a new raster has been added to the screen, which is reprojected to the correct projection. At this point, I advise you to save your QGIS project. Next, we need to make sure our projection for the whole file again matches the coordinate reference system we've changed to. Here, we can see that mine does not. It is currently in WGS 84, so I'll change this by clicking on this, and then setting it to 29 North, pressing OK. So we're now set up to create our buffers. To create our buffers, we need to go to Vector, Geoprocessing Tools, and Buffer. This opens up the buffer window, which looks something like this. We need to set our input layer to our projected health facilities layer, and then we need to set our distance to the correct distance. In this case, we're looking to do 5km, which in meters is 5,000. We can then save the default settings for the other parameters as they are. So no changes are required for segments, end cap style, join style, or mitre limit. But under Buffered, we want to change the name and save it to our output. So we click on the Browse button and go to Save to File. In our DHRs2 training, we can save this as a geojaton once again, and save this as Damer, Facilities, Buffer, and press Save. We'll then run this and press Close. As you can see, a buffer has been produced of 5km around our health facilities. We can visualize this so it's more easy on the eye and understandable for a GIS user by double clicking. And on the Opacity, changing this so it's somewhere around 50% and press Apply. As you can see, this now allows us to see through the buffer and it also allows us to see areas of overlap. We have now produced a buffer of 5km around our health facilities. We can now move on to calculating the population that is found within the buffer zone around each facility. To do this, we go to Raster Analysis in our Processing Toolbox, which can be accessed via Processing and then Toolbox. So we need to go to Raster Analysis and scroll down to Zonal Statistics. In Zonal Statistics, we need to set our input layer as our buffered facilities. So here I'm going to select Damer, Facilities, Buffer, and the raster layer needs to be our re-projected population surface. So for me, I'm going to select the Sierra Leone, Population Per Pixel, 2020, UN Adjusted, Constrained, Underscore, UTM 29 North Layer. Within the Output Column prefix, I'm going to again, as we did in the earlier video, type pop underscore. I'm going to make sure that the statistics being calculated are countsum and mean. And then I'm going to ensure I'm saving this in an appropriate way. So if I click on our Browse to Save to File, this will then allow me to save it as a GeoJSON and I'll call it Damer, Facilities, Population in Buffer. And press Save. I'll then run the tool and close this window. Here you can see that the buffers have changed colour, and that's because a new dataset has been added to our layers window. And this is the calculated population for the buffer. So if we right-click this, we're able to go to Open Attribute Table. And from this, we can see within each health facility point and buffered area, the population that was worked out by our zone or statistics calculation. And in this case, we're able to see that the count in this first buffered zone is 7,519 people. And we're able to know that because each of the population pixels that sits within the buffered area is calculated and summed to produce this final value. So that's the end of this video. Within this video, you've learnt how to project your datasets quickly by saving a new layer. You've learnt how to create a buffer and you've learnt how to calculate the population within the buffer. You can now save your project and that's the end of the video.