Add band from another product


I am conducting machine learning with SNAP and I would like to test k means with a combination of principal components and band ratios. I saw a post explaining that a band from another product can be added to the original one by the use of band math, but I don´t really see how. My goal is to have in the same product some band ratios and some principal componentes in order to perform k means.
Can this be done in SNAP?

thanks a lot


you can add a band if the raster size of this band is the same that a raster size in the original product. For doing that, in “BandMath->Edit Expression…” you have to select the product that contains the band you want to add:

The ComboBox will show you only the compatible products.