The NDII operator algorithm computes the Normalized Difference Infrared Index from a given product.

The NDII results from the following equation:

NDII = (N - S1) / (N + S1)

, where:

The bands are:

- N is the NIR band
- S1 is the SWIR 1 band

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

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