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CWSI Index

What should be the list of bands with index calcalutor to calculate water stress index crop using thermal sensor?

A thermal sensor typically has a single band, which is the infrared band (also named “thermal_ir” sometimes). 

I am not a specialist of CWSI, but from what I could read there seem to be different versions of the formula. This paper for example gives three definitions (the Idso empirical model, the Jackson theoretical model, and the new Alves model): http://sourcedb.cas.cn/sourcedb_igsnrr_cas/yw/lw/200906/P020090625730049623318.pdf

In each of these the canopy temperature seems to be an important factor, which from my understanding is what you are measuring with the thermal sensor. In that case, you would have to compute the temperature based on the infrared band (as described here: https://support.pix4d.com/hc/en-us/articles/208592186-Thermal-projects-FAQ#label2) and then plug it in the formula you have chosen to use for CSWI. The formula can be added in the Index Calculator as described here: https://support.pix4d.com/hc/en-us/articles/202560489

Maybe if you could give more information about the CWSI formula you plan to use, as well as the camera you are using it could help to better understand how to proceed. 

Maybe someone else from the Community with experience working with CWSI could give us more insights.

Thanks for help us.

Your pdf was very useful.