 Hello, this is Hans van der Kwaas, junior lecturer at IHE Delft Institute for Water Education. In this video I'm going to demonstrate how to use lookup tables with combination of different raster layers. In this example we'll look for wells that are accessible. They should be less than 40 meters deep, within 150 meters from houses, within 150 meters from roads, and they should be at least 300 meters from industry. In previous videos we've done this exercise using Boolean logic, a map algebra using the raster calculator. Here I'll show you that you can do this very easily using lookup tables with multiple raster layers. So I used the lookup tool from PC Raster, and I check here the boxes of the layers that I want to use, all of them in this case. You could also click select all. Now I can make a lookup table in Notepad, and each column of the table corresponds with values in the layers in the order of the tool. So a 1 for houses 150 meters to indicate that that should be true. For in-dist we're looking for larger than 300, and for the third one, roads 150 meters, we want it to be 1 for true, and for well depth we are looking for less than 40 meters, and I also use 40 included, and then the output will be 1 Boolean true. So you see it's very easy to write these lookup tables if you know how to make ranges. So the less than and larger than means it does not include the value of the range, and the square brackets includes the value of the range, and when we have Boolean or nominal or ordinal we can just use a specific value, as we did here for houses and roads. And then the last column contains the output value, and then later in the tool you can indicate if that output is Boolean, nominal, ordinal, scalar, directional, or LDD. In this case it's Boolean. Let's save the result. So these lookup tables are just very simple text files. You can give it any extension. If you use Notepad you can keep it like this, and then we choose the lookup table, we choose the output data type which is Boolean, and I save it to accessible wells. That will be our output Boolean file. I click run, and now with a bit of styling we can make it visible, and these are the three accessible wells in the study area. So a very different way than using mapLGB on the raster calculator, but also a very easy way to apply a lookup table with multiple layers.