The VrNIRBI operator algorithm computes the Visible Red-Based Built-Up Index from a given product.

The VrNIRBI results from the following equation:

VrNIRBI = (R - N) / (R + N)

, where:

The bands are:

- R is the Red band
- N is the NIR band

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

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