reduce: Reduce dimensionality of raster layers.

In gecko: Geographical Ecology and Conservation Knowledge Online

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

reduce(layers, method = "pca", n = NULL, thres = NULL)

Arguments

layers	SpatRaster. As defined in package terra, see terra::rast().
method	character. Either Principal Components Analysis ("pca", default) or Pearson's correlation ("cor").
n	numeric. Number of layers to reduce to.
thres	numeric. 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 read function, only landcover is reduced by using only the dominating landuse of each cell.

Value

SpatRaster.

gecko documentation built on April 4, 2025, 2:22 a.m.