The UI operator algorithm computes the Urban Index from a given product.

The UI results from the following equation:

UI = (S2 - N) / (S2 + N)

, where:

The bands are:

- N is the NIR band
- S2 is the SWIR 2 band

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

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