recstrat_regl: Random Ecologically Stratified Sampling of equal numbers

In filBe87/PKUss: Helper functions for species distribution modelling practicals of the Peking Unversity summer school 2019

Description

This function randomly takes an equal number of samples per class in the stratification layer.

Usage

recstrat_regl(in_grid, sample_no)

Arguments

in_grid	The stratification grid to be sampled.
sample_no	The total number of pixels to be sampled.

Details

The number of classes in the stratification layer is determined automatically from the integer input map. If the number of pixels in a class is higher than the number of samples, then a random selection without re-substitution is performed, otherwise all pixels of that class are selected.

Value

Returns a dataframe with the selected sampling locations their coordinates and the strata they belong in.

Author(s)

Achilleas Psomas, Niklaus Zimmermann

Examples

bio3<- raster(system.file("external/bioclim/current/bio3.grd",package="biomod2"))
bio12<- raster(system.file("external/bioclim/current/bio12.grd",package="biomod2"))
B3.rcl<-rcls.grd(bio3,9)
B12.rcl<-rcls.grd(bio12,9)
B3B12.comb <- B12.rcl+B3.rcl*10
B3B12.regl_samples <- recstrat_prop(B3B12.comb,100)
plot(B3B12.comb)
points(B3B12.regl_samples$x,B3B12.regl_samples$y,pch=16,cex=0.6,col=B3B12.regl_samples$class)

filBe87/PKUss documentation built on June 29, 2019, 12:12 a.m.