Figure 3
The Italian peninsula is covered by large cells (5000 km2 each) to perform a hold-out spatial CV procedure. Training and validation examples were assigned to different cells so that the model would not be trained on adjacent grid points (except for points along the cell borders). Furthermore, training examples were subsampled to ensure a balanced ratio between the two classes. The map was produced by using the plot.raster function from "raster" R package.
