Tutorial: Spatial Analysis of Accessibility of Wells using Map Algebra

4. Condition 2: No Industry, Mine, or Landfill within 300 Meters from Wells

4.1. Create a Boolean Raster with True for Industry, Mine, and Landfill, and False for Other Buildings

1. Choose in the Processing Toolbox Raster analysis | Reclassify by table.

reclassify by table menu

The Reclassify table dialogue appears. We are going to reclassify the buildg raster using a lookup table.

2. Fill in the dialogue exactly as in the figure below.

reclassify by table

Here you can identify a nodata value for the output layer for values that are excluded from the lookup table. The Range boundaries define if values are included or excluded from the ranges in a row of the lookup table. Here we don't use ranges, but reclassify each value. Therefore we choose min <= value <= max. For the Output data type we use Int16 because the output values are whole numbers.

3. Then go to Lookup table and click Browse button.

4. Fill in the lookup table as shown in the figure below.
lookup table

5. Click OK and Run. Close the dialogue when the processing is finished.

6. Check the result: 1 for mines, industry, and landfills, 0 for the other classes. Use the Identify tool identify tool buttonand click on the map. On the lower right panel you can find the identify results. It displays the value of the pixel of the selected layer in the Layers panel. You might have to resize the columns to see the pixel values.

As you can see the industry is a Boolean layer, so we need to style it with Paletted/Unique Values renderer as we did before.

7. Style the industry layer.