Reduce the number of layers by either performing a PCA on them or by eliminating highly correlated ones.
raster.reduce(layers, method = "pca", n = NULL, thres = NULL)
A RasterStack object.
Raster* object as defined by package raster.
Either Principal Components Analysis ("pca", default) or Pearson's correlation ("cor").
Number of layers to reduce to.
Value for pairwise Pearson's correlation above which one of the layers (randomly selected) is eliminated.
Using a large number of explanatory variables in models with few records may lead to overfitting. This function allows to avoid it as much as possible. If both n and thres are given, n has priority. If method is not recognized and layers come from raster.read function, only landcover is reduced by using only the dominating landuse of each cell.