 Hello, in this video we're going to create and style a flow direction map. We'll derive the flow direction from a DEM, we use the LDD create tool for that. The LDD create tool will fill the things and result in the flow direction. If you're interested in the filled DEM, you need to use the LDD create DEM tool. In this case we don't need it, so we use the LDD create tool. Each PCRuster tool has a link to the documentation, which is quite complete. So here we can see all the parameters that are needed for the tool and the description of what they mean. It also gives the encoding of the flow direction which corresponds with the numerical pad of your keyboard. Here is an explanation of the arguments of the tool and there are examples of the calculation. In our case make sure that you have the DEM in the PCRuster format, a scalar map and we keep all the defaults to fill all the things and then we define the output file name. Call it flowdirection.map for the PCRuster format and click run. This takes some time, but when it's finished it will appear in the map canvas. The next step is to style it and to add the compass directions. The flow direction is encoded in integer values and therefore we need to use the palleted unique values renderer. If I click classify each of the direction numbers values get a unique color and a label. We are going to further process that using the attribute table. So I create a raster attribute table, I click open raster attribute table and here I can change the colors of the directions and add class names with the compass directions. So I'm going to do a fast forward here to add the colors and the names, but you can later add the RGB colors from this final attribute table. Names of the compass directions and I use this then to classify the raster and here the colors are added as well as the names of the compass directions. But it's still very difficult to interpret such a colorful map. I can add the shading from the hill shade by using some blending, just make sure that it's only blending with the hill shade and with nothing else. There we get a bit of a shading impression, you can make it smoother by changing the resampling to zoomed in bilinear. You can still improve the visualization by using arrows instead of colors. Therefore we need to install the crayfish plugin. This plugin has tools to deal with mesh layers and we can convert the pcraster flow direction format to a mesh. Therefore we choose here from the process in Toolbox pcraster ldd to grip, a very simple tool where we only need to specify the output file name of the grip file. Call it flowdare mesh not to get confused with the raster format. Close the dialog when it's done. It's not automatically added to the layers panel, so we need to look it up in the browser panel. And there we find it and we expand the flowdare mesh section and drag the mesh layer to the map canvas. It will take some time to load and then it shows up in yellow. When we switch off the contours and we switch on the vectors, it will be filled with arrows and will be turned into black. But now under the vectors tab we can tweak the arrows to make more sense out of this. First we can modify the arrow length and give it a fixed length and let's start with changing it to one pixel. Then when we zoom in we see that now each pixel has an arrow. You can also display the arrows on a user grid and we can play with these values to improve it and we can also change the color of the arrows. You can use blue and you can even visualize this in the 3D view. You can also visualize it as streamlines or as traces. So in this video you've learned how to create a flow direction map and to style it with a directional ramp or use the crayfish plugin to export it to mesh format and style it with arrows, streamlines and traces.