Linear regression for each pixel 'slice' through a DataArray

[Robin Wilson]

Hi,

I've got a DataArray with three dimensions: x, y and time. I'd like to do a linear regression for the value at each (x, y) location over time - so I get a slope and intercept value for each 'pixel' of my data. To make things more interesting, each (x, y) location has missing data at some time periods.

I can't see any built-in method, and approaches using numpy seem to suggest just looping over pixels (for example, see http://stackoverflow.com/questions/34177648/python-how-to-perform-linear-regression-of-two-numpy-3d-datasets-along-axis).

What's the best way to do this using a DataArray? Would it just involve just grabbing the values and the time index from the DataArray and then looping over these? Is there a better way?

I imagine I can't be the first person who has tried to do this in xarray - any advice would be much appreciated,

Cheers,

Robin

[Ryan Abernathey]

Robin,

I think this thread covers the issue:

https://groups.google.com/forum/#!topic/xarray/fz7HHgpgwk0

-Ryan

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[Robin Wilson]

Hi Ryan,

Thanks for the link - that's perfect! (I did do some searching of the list archives first, but unfortunately my search terms didn't turn up that thread - sorry!)

Thanks,

Robin

To view this discussion on the web visit https://groups.google.com/d/msgid/xarray/CAJAZx5DDA8o%2B4e2RjFSd8ZyvNWWzCmD5ku-ZiXKCj_%3DL3eTpqQ%40mail.gmail.com.

[Aleš Kuchař]

Hi Robin,

you can check my very preliminary example how to couple xarray package with linear regression function from statsmodels package here. It may help you somehow. 

Best,

Ales

Dne středa 13. července 2016 13:04:29 UTC+2 Robin Wilson napsal(a):

[Edward]

Thank you Ales - beauty!