MNDWI Algorithm Specification

MNDWI

The Modified Normalized Difference Water Index algorithm was developed by Xu, 2006 and can enhance open water features while efficiently suppressing and even removing built-up land noise as well as vegetation and soil noise.

The greater enhancement of water in the MNDWI-image will result in more accurate extraction of open water features
as the built-up land, soil and vegetation all negative values and thus are notably suppressed and even removed.

The MNDWI results from the following equation:

MNDWI = (green_factor * green - mir_factor * middle_IR) / (green_factor * green + mir_factor * middle_IR)

MNDWI-Flags

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

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