Add PCA for STEPPS output

[andydawson]

STEPPS output in Albers coordinate system. Reproject to lat-long and then do PCA (or maybe do PCA and then reproject?).

[SimonGoring]

Why does projection in lat/long make it better for PCA? Or is this two steps? PCA on the time series, then plot against lat/long?

[andydawson]

I have to do both steps to compare with ecosystem model output. Just trying to think about which order to do them in. And no time series, just settlement era.

The reason I'm thinking about this is because I think that projecting a raster to a new grid uses interpolation. I don't think I want to interpolate PCA scores, so I think I need to reproject to new grid and then do PCA. Right?

[andydawson]

For now just reprojected and did PCA on the native STEPPS grid. Do we even need STEPPS scores on the same grid as the model output?

See commit: 7aba3ac