I am working with some MODIS imagery for a project (I'm relatively new to remote sensing) using MOD09GA, and hoping to apply a melt area detection index (MADI) to images to calculate melt day length for different years. This was done in a paper by McCabe et al in 2010, where they present the equation for this. It simply divides band 1 by band 7, but I have no idea how to do this in ArcMap or ERDAS Imagine.
Looking for tips on how I would go about this. Do I need to create a composite bands image, or use raster calculator?