 Hello, this is Hans van der Kost, Senior Lecturer at IHE Delft Institute for Water Education. In a previous video and webinar I've showed how to use the raster calculator to do map algebra for spatial analysis. In this video, I'm going to do the same, but I'll use other tools. Instead of the default raster calculator, I will use the raster calculator from the processing toolbox, and I will make a graphical model using the tool in the processing toolbox to create those, so the end user can then play around with it in an interface. So this time we are going to use the raster calculator from the processing toolbox to do the calculations with map algebra, so you find it in the raster analysis. And then the first thing is to filter out the houses. So this building layer has several classes, and class number one is houses. I choose here the layers that I want to use to set the extents and the projection, etc. That's necessary for map algebra. And here I choose the output name. I can choose different raster formats, and I call the output houses.tiff, and then I can run it, and I can go back to the parameters. Everything stays the same, except that I now need the industry, which is with pixels larger or equal to 3, and I keep the other things as they are, and I just need to change the file name, and I call this then industry. So boolean map with true for industry and false for not industry. I run it, then I go back, and now we need the roads. We know that the road map has two classes, and if it's larger than zero, no roads, then it's roads, so I call this one isroads, and I run it. The next one that we need is to calculate the well depth, and that's TTM minus groundwater level, then we get the depth of the well, it's reference to the surface level, and I call it well depth, for the rest I keep everything default. I run. So now we have a set of boolean input layers that we then need to calculate the proximity and the distance, and I'm going to use in this case the graphical modeler from QGIS. I need to give the modeler a name, so I call it accessible wells, and you need to give the group name for how it shows up in the tool box, in the processing tool box. So first I need to identify the inputs, so these are raster layers, the first one is the one with the houses, and you see it puts these graphical blocks in there. The second one is the roads, then the third one is industry, and then the fourth one is the well depth, and then we need to use some processing tools, we find them under the TAP algorithms, and we need to do some proximity analysis that we didn't do yet, so I add the proximity, we change the description, so that's distance from houses, input layer is then houses, so it will be linked to that one, we use the geo-referenced coordinates, you see these are the same dialogue fields that we have in the normal tool, and there I put 150 meters, and then true for the cells that are within 150 meters and zero for the other ones, I don't specify an output map, because we're still going to use that output, then distance to the roads, and the input layer is then roads, use geo-referenced coordinates, and again 150 meters, true and false, true when it's within 150 meters and false when it's further, so also better to change this to distance to the houses. Next we need proximity also for the industry, distance from industry, we want to be 300 meters or further, we previously can't do that directly in this tool, so we calculate only all the distances in geo-referenced coordinates, so we have them in meters, simply click okay, there it is, next step is to use the raster calculator to calculate a few more things that we need to calculate, so change the description, more than 300 meters from industry, that's also the title of that little block that it will create, so that's always nice, and if we refer to that then we'll see that, so like here the distance from industry should be larger or equal in 300, and I choose the input layer as the reference for cell size and extent etc, and then I click okay, and you see it's automatically linked because we specify the input as the output from the distance from industry as another one, and the weld depth should be less than 40 meters, we choose a reference, normally the output from the one that you use here as an input, okay they're linked, so you see we still have to change the name, raster calculator is a default name and if you want to refer to that it's better to give it a less generic name, welds less than 40 meters, okay, and now you can use the raster calculator to do some Boolean logic there, so we add all those results, sure that you choose the right one, that one of course, and choose the reference layers, just choose all the inputs that I used, there it is, because it's an output I also need to define the name of the field of the output layer, let's call it accessible welds, and that green block is then the output, the end result, there's a few more things that we can do, we can use variables for the distance criteria, let's make one distance to houses, it's a number parameter, and a minimum value of 0 and a maximum of 2000 with a default of 150, and you see it's added as a yellow block because it's an input, you can drag it somewhere convenient, and then I can edit the one that uses that value, and I choose here model input, and then I can choose distance to houses, and it will use then that value as a default, do the same for the roads, and also change that to model input, distance to roads, and then they are linked, let's save the model, it automatically goes somewhere in your profile, and let's run the model, so we see here the dialog, and I can fill in the layers that we need, see the default value is there, and then I can calculate the accessible wells, there it is, we can style it, we see the same result as what we had in the other approach, but now it's more automated, if the end user has QGIS, you can use this tool and simply fill in all the layers and play around with the criteria, let's change, let's create one with 100 meter distance to houses, and only 50 meters from the roads, paste the style, you can even include the styling in the graphical modeler, and there we see that now it's reduced to two suitable wells instead of three, so I hope this was useful, there are more nice videos on the YouTube channel, so please subscribe if you want to see more, for more free materials you can go to isgdelftopencorsairforgis at gisopencorsair.org