Greetings,

I computed the Soil Moisture Index for my Study Area using an article [1]. After that I just simply calculated NDWI for the same Study Area just to check the differences. I was confused because I couldn't see an important disparity, and I spent a lot of time computing SMI. Water stress and water logging areas were similar in both of my indices, as we can see from the pictures bellow. May someone inform me about why there are so slightly differences, and why do we use SMI instead of just having other easier moisture indices (like I did with NDWI)?

Thank you for your time, appreciate your help.

Article:

[1][ Estimation and evaluation of high spatial resolution surface soil moisture using multi-sensor multi-resolution approach - ScienceDirect