7.9.5. Conditional expressions using the raster calculator
Let’s now analyse the area covered by some land use types of interest (arable land, forests) within the buffer zones of our honey bee colonies (see section 6.9.6. for more information).
- Open the menu Raster > Raster calculator.
- Combine Raster bands and Operators until the Raster calculator expression equals “CLC06_Fribourg@12 = 211” (211 is the raster value for “non-irrigated arable land in the CLC06 dataset).
- Specify an Output layer, e.g. CLC06_class211.tif.
- Activate the Raster band CLC06_Fribourg@1 again and click Current layer extent to make sure that the output layer has the same extent as the source.
- Verify that the parameters are set according to Fig. 113 and click OK to start the calculation.
- Double-click on the new greyscale Layer CLC06_class211 to open the Layer Properties > Tab Style.
- Check Estimate (faster) within Load min/max values from band and click Load, select Stretch to MinMax in the Contrast enhancement (see section 7.3.3.).
- Click Apply to make the layer styling effective and close the Layer Properties dialog with OK.
- Repeat steps 29 to 36 with the following raster values: 24 (class 312,
Coniferous forest) and 25 (class 313, Mixed forest).
Fig. 113. Separating bands of interest out of the CORINE Land Cover 2006 data set. The raster value 12 equals the category “211 - Non-irrigated arable land”.