raster.reduce: Reduce dimensionality of raster layers.
Description
Reduce the number of layers by either performing a PCA on them or by eliminating highly correlated ones.
Usage
raster.reduce(layers, method = "pca", n = NULL, thres = NULL)
Arguments
layers
Raster* object as defined by package raster.
method
Either Principal Components Analysis (pca, default) or Pearson's correlation (cor).
n
Number of layers to reduce to.
thres
Value for pairwise Pearson's correlation above which one of the layers (randomly selected) is eliminated.
Value
A RasterStack object.
Details
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.