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Comparing the NDVI on satellite imagery from two years, but can't change maximum value.

Question asked by mfeldma000@citymail.cuny.edu_ccny on Mar 13, 2020

Hi everyone. I'm looking at a satellite image of crop images from 2014 and another from 2019. The location is near the Salton Sea Southern California. One image was taken in 2014 and the other was 2019.

 

When I compare the NDVI from both years the surrounding area in 2019 looks mostly green, while it comes out orange in 2014. In order for this to make sense, the desert would have had to become vastly more green during that time. Highly unlikely.

 

I think what is happening is that I can't get the values on the symbol index to correspond. In my attached screenshots I circled the max. value on the 2019 page which is 0.229288. Unless I'm mistaken, shouldn't it be 1, just like it is in the 2014 screenshot? I have tried toggling pretty much every setting but cannot get it to change. What should I do? I should probably mention that I'm a student with very little experience working with satellite images. This is for a class. Thank you! 

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