The WI2 operator algorithm computes the Water Index 2 from a given product.

The WI2 results from the following equation:

WI2 = (B - S2) / (B + S2)

, where:

The bands are:

- B is the Blue band
- S2 is the SWIR 2 band

Also the processor computes an additional flags band called 'wi2_flags' with the following bit coding:

Bit Position	Description
Bit 0	The computed value for WI2 is NAN or is Infinite
Bit 1	The computed value for WI2 is less than -1 (minus one)
Bit 2	The computed value for WI2 is greater than 1 (one)