Edzer Pebesma wrote:
Markus, a few notes:
- if you do PCA on uncentered data, by computing the eigenvalues of the
uncentered covariance matrix, this implies that bands with a larger mean
will get more influence on the final PCAs. I have sofar not managed
finding an argument why this would be
Markus:
It seems that i.pca output is supposed to be identical to
prcomp(center=FALSE, scale=FALSE) output in R, because a PCA is
scale-sensitive and the eigenvalue as reported by i.pca is the variance
of the raw, unstandardised data.
The thing is that with the SPOT data all seems fine and
