The DSI operator algorithm computes the Drought Stress Index from a given product.

The DSI results from the following equation:

DSI = S1 / N

, where:

The bands are:

- N is the NIR band
- S1 is the SWIR 1 band

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

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