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://geospatialpython.googlecode.com/files/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:
Start QGIS.
From the Plugins menu, select Python Console.
In the Python Console, load the layer and ensure that it is valid:
rasterLyr = QgsRasterLayer("/qgis_data/rasters/satimage.tif", "Sat Image") rasterLyr.isValid()
Now, get the band count, which should be
3in 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. Most sequences within a programming context start with 0.
