 Hello, in this video we are going to delineate the catchment of a specified Outlet pixel. We will use the PC Raster Tools plugin, go to the Processing Toolbox and under Hydrological and Material Transport Operations choose the Catchment tool. For the LDD layer we choose the Flow Direction layer. For the Outlet layer we choose our Outlet Raster. The Outlet Raster can be in Boolean, Nominal or Ordinal Raster format and that format determines also the format of the output catchment layer. In our case we use a Nominal Outlet layer so the catchment layer will also be Nominal. Let's run the tool and zoom to the extent of the catchment layer and here we see our catchment. It has value 1 for inside the catchment and value 0 for outside the catchment. Let's add some styling because this is Nominal we use palleted unique values and we see indeed that it has values 0 and 1. Now it's much nicer to look at the catchment boundary in a polygon format so we have to change it to vector using the Polygonize tool. So choose the catchment as input and define an output name and we choose here the Shapefile format and call it Rule Catchment and we run the tool and this is the result Polygon Shapefile. So let's have a look at the attribute table. You would expect to see only two features there, 1 and 0 but it has more and it has to do with artifacts created during the polygonization of the Raster. If I zoom to one of those features you can see here that the boundary makes a loop which is exactly one pixel. So what we need to do is find out which feature is our catchment, invert the selection and remove all the other features so in the end we only have the catchment boundary polygon. Toggle off the editing and save the edits. If I remove the background Raster you can see that here we have the remaining catchment boundary polygon but it also has a hole in it which is caused by the mine that exists in this area and the filling sinks algorithm of LDD create were not able to fill this whole area and it created its own subcatchment. We can remove it by deleting the ring from the advanced digitizing toolbar which I had added by clicking right on the toolbar. Save those edits and here we have our catchment boundary polygon layer. So in this video you've learned how to delineate the catchment of a specified pixel and to convert it to a vector polygon format.