I work on indices with Sentinel-2 data and I found out a thing that forced me to fill some doubts. For many indices SNAP provides the bands by default and for GEMI index it suggests to use 8A band as NIR. But 8A is a Vegetation Red Edge band. NIR band is 8. So, I wonder if it’s a mistake and I have to use Band 8 for GEMI, or SNAP knows what to do and I have to use 8A.