The NWI operator algorithm computes the New Water Index from a given product.

The NWI results from the following equation:

NWI = (B - (N + S1 + S2)) / (B + (N + S1 + S2))

, where:

The bands are:

- B is the Blue band
- N is the NIR band
- S1 is the SWIR 1 band
- S2 is the SWIR 2 band

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

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