What is NGDR index?

1

Hello

I have seen several scripts use create an index called NGDR (and it has been defined slightly differently between scripts). What is NGDR? I can’t seem to find a reference for it.

Thanks

2

Dear @pman,

I assume you are referring to the scripts that are used in the FIS for cloud detection. Those scripts all based on Braaten-Cohen-Yang cloud detector.

You can find more info in it in our custom-script repository where we also link the original research article.

As you will see there the NDGR was in the original paper used as a Normalized Difference index of the Green and Red band and therefore the acronym.

Best,
Daniel

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3

Thank you. In script I saw, the position of the G and D were swapped. :slight_smile:

4

Small addition: Depending on which collection the script is used, different band numbers might correspond to the Green or Red band. You can info on which band corresponds to which wavelength in our documentation (e.g. here for Sentinel 2 L2A).

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