raster.reduce: Reduce dimensionality of raster layers.

In red: IUCN Redlisting Tools

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.

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.

Value

A RasterStack object.

red documentation built on Sept. 9, 2023, 1:07 a.m.