Counting raster bands

A raster might have one or more bands. Bands represent layers of information within a raster. Each band has the same number of columns and rows.

Getting ready

We will again use the SatImage raster available at https://github.com/GeospatialPython/Learn/raw/master/SatImage.zip.

Place this raster in your /qgis_data/rasters directory.

How to do it...

We will load the layer and then print the band count to the console. To do this, we need to perform the following steps:

1. Start QGIS.

2. From the Plugins menu, select Python Console.

3. In the Python console, load the layer and ensure that it is valid:

           rasterLyr = QgsRasterLayer("/qgis_data/rasters/satimage.tif",
                                      "Sat Image") 
           rasterLyr.isValid() 
   

4. Now, get the band count, which should be 3 in this case:

           rasterLyr.bandCount() 
   

How it works...

It is important to note that raster bands are not zero-based indexes. When you want to access the first band, you reference it as 1 instead of 0...