NDWI2 Algorithm Specification |

### NDWI2

The second Normalized Difference Water Index algorithm was developed by McFeeters (1996) to detect surface waters in wetland environments and to allow for the measurement of surface water extent .

The NDWI2 results from the following equation:

NDWI2 = (green_factor * green - IR_factor * near_IR) / (green_factor * green + IR_factor * near_IR)

### NDWI2-Flags

Also the processor computes an additional flags band called 'ndwi2_flags' with the following bit coding:

Bit Position | Description
--- | ---
Bit 0 | The computed value for NDWI2 is NAN or is Infinite
Bit 1 | The computed value for NDWI2 is less than -1 (minus one)
Bit 2 | The computed value for NDWI2 is greater than 1 (one)