 Hello, this is Hans van der Kwas, senior lecturer at IHE Delft Institute for Water Education. This video I'm going to demonstrate how to snap pour points and delineate multiple catchments of those points in QGIS. This feature was requested a lot, especially from people who use ArcGIS, where this is a functionality, but it's also quite easily possible to do it in QGIS using a plugin that I made in Acorunia during a hackfest, and that is available through GitHub. The link is provided in the text of this video. So in this exercise we need the filled DEM from the catchment delineation process, the hydrologically corrected DEM, and we need the delineated channels, and we need the open street map as a background, because there you want to define the points at the outlets of your subcatchments. Then you need this tool from my GitHub site, the points to catchments plugin. It's not in the official plugin repository, but basically what you need to do is to copy the points to catchments folder to your plugins folder in your profile in QGIS. So you download the zip file and you can then extract it to the folder where your profile stores the plugins. You can find that location by going to settings and then options, and then there you find the path to your QGIS profile. So in my case it's there and it's extracted in this folder, so you have to look for the Python folder in your profile and then the plugins subfolder, and there you extract the points to catchments folder. Then you can go to the plugins menu and manage plugins and look for that plugin, point to catchment, and then you can check the box and it's now activated. It's a processing plugin, so you find it in the processing toolbox. There's a new tool set, IHE Delft Hydrology, and there you can find calculate catchments from points. So we need a layer with points. These are points you can digitize on OpenStreetMap to indicate the outlets. So here we have a few of those points, so you can see that they are digitized at the outlets on your OpenStreetMap, but the delineated stream is offset because that doesn't take care of human influences and there might be other errors. So the next step is to snap those points to the delineated streams. That's basically what you do with the snapPorePoints function. So we look for snap and then you can use snap geometries to layer and as an input layer we use the pour points because we want to snap those to the reference layer, the channels and we increase the tolerance to 100 meters. Here you can also control the behavior of the snapping. We keep it at the default so you can play around with that and then we save it to a new file and I call it snappedPorePoints in a shapefile, you can also use a geo package. It's quite fast that algorithm, now let's zoom in on those points and see what happened and there we see indeed that the points were snapped nicely to the nodes on the line, so it doesn't snap to the segments but to the nodes. That's a choice, so it's nicely snapped and now we can run the algorithm to delineate iteratively the catchments from those points. So we use the snappedPorePoints as the outflow point layer, then we use the filled DEM as the DEM layer and we have to choose a folder where it's going to store the shapefiles, make a new folder called output and I run it, that takes a while. Basically what it does it iteratively runs this upslope function from saga but each time with another coordinate from the points that we have indicated to use. We need to refresh the browser and now we see the output folder and then I can drag these four areas to the map canvas and we can look at them and we see that each belongs now to one of those snapped outlets. I hope you enjoyed the video, if you like these videos you can subscribe to my YouTube channel and get updates when there are new videos posted. For more free materials please go to the IHE Delft OpenCourseWare on GIS which is at GISOpenCourseWare.org. Thanks for watching and I'll see you in the next video.