The GRNDVI operator algorithm computes the Green-Red Normalized Difference Vegetation Index from a given product.

The GRNDVI results from the following equation:

GRNDVI = (N - (G + R)) / (N + (G + R))

, where:

The bands are:

- G is the Green band
- R is the Red band
- N is the NIR band

Also the processor computes an additional flags band called 'grndvi_flags' with the following bit coding:

Bit Position	Description
Bit 0	The computed value for GRNDVI is NAN or is Infinite
Bit 1	The computed value for GRNDVI is less than -1 (minus one)
Bit 2	The computed value for GRNDVI is greater than 1 (one)