[R-sig-Geo] PCA on rasterStack

[Maurizio Marchi]

Hi everybody,
I need to perform a Principal Component Analysis on some climatic maps (20
layers). I use the "prcomp" function of stats package with the na.omit
option and everithing works fine but I need help concerning data scaling
and centering. I have both temperatures and precipitation maps, so I
decided to scale the data (scale=TRUE) but should I also use the centering
option (center=TRUE)? In my advise, the scaling procedure should also
center my data...the scaling procedure is made subtracting the mean and
dividing for the variance, isn't it?

many thanks,

-- 
Maurizio Marchi
Calenzano (FI) - Italy
ID Skype: maurizioxyz
Ubuntu 14.04 LTS
linux user 552742

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