Random Ecologically Stratified Sampling of equal numbers
This function randomly takes an equal number of samples per class in the stratification layer.
ecospat.recstrat_regl(in_grid, sample_no)
in_grid |
The stratification grid to be sampled. |
sample_no |
The total number of pixels to be sampled. |
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.
Returns a dataframe with the selected sampling locations their coordinates and the strata they belong in.
Achilleas Psomas achilleas.psomas@wsl.ch and Niklaus E. Zimmermann niklaus.zimmermann@wsl.ch
library(raster)
library(classInt)
bio3<- raster(system.file("external/bioclim/current/bio3.grd",package="biomod2"))
bio12<- raster(system.file("external/bioclim/current/bio12.grd",package="biomod2"))
B3.rcl<-ecospat.rcls.grd(bio3,9)
B12.rcl<-ecospat.rcls.grd(bio12,9)
B3B12.comb <- B12.rcl+B3.rcl*10
B3B12.regl_samples <- ecospat.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)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.