Normalized diff function - What order would a user expect the bands to be in? about earthpy HOT 8 CLOSED

I think the doc is perfect, but the order of the arguments should be reversed. I think this is more intuitive since b2 comes first in the numerator and denominator for the normalized difference equation.

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see PR #44

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I wouldn't have any strong prior expectations for the ordering of bands for a function like this.

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it is more subjective... as long as the doc is clear on which bands go where in the equation, which I think it is. seeing the equation (b2 - b1) / (b2 + b1), implies to me, that the the args should come in as b2 and then b1, but that's a little weird since it sounds like you're counting backwards and we read left to right.

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I agree with Joe that it is more intuitive for b2 to be provided as the first argument, and then b1 as the second. As he said, this matches the actual structure of the equation.

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just a note all that in line with @joemcglinchy 's original thought and @jlpalomino 's second.... that the order of bands in the norm_diff function is confusing... several students have voiced the same issue! This is why i originally created this issue. @joemcglinchy i know you made some changes... Do you want to resubmit the PR to adjust the function and also update the docs, here and we can then decide when to merge it the students have an assignment where they will likely use it starting today. but after thanksgiving could be a good time to merge this. then we'd want to update our lessons too. not a big deal to do tho!

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@jlpalomino assigning this issue to you when you add tests for norm_diff please also just swap the parameter order!

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referencing this pr which has the changes implemented. - #140

@jlpalomino will you please also close this issue when the PR is merged!

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