I was trying to learn unsupervised classification in QGIS 2.6 following the tutorial video: https://www.youtube.com/watch?v=mI80eENtWSE When trying myself, clicked Run during the process it shows the message, "Input layer ag020522_DPAC has more than one band. Multiband layers are not supported by SAGA". But it seems like during the tutorial the image used was Multiband layers. Am I right? Do I need to process the data anyhow first? I downloaded the data from this link: https://github.com/FOSS4GAcademy/GST101FOSS4GLabs.
I found this at the QGIS 2.2 documentation at "Limitation for multi-band layers"
Obviously there is a limitation of multi band layers, what means that they are not supported. As a work around one can extract every single band with the raster calculator
Raster > Raster Calculator.
Save each raster-band as a single tif-file an load it in the QGIS-project.Now the SAGA Cluster analysis is performable by selecting those three rasters in the
Multi selction window.