raster (version 1.1.7)

Sample: Random or regular sample

Description

Take a random or systematic sample the values from a Raster object.

Usage

sampleRandom(x, size,...)
sampleRegular(x, size, extent=NULL, cells=FALSE, asRaster=FALSE, corners=FALSE)

Arguments

x
a Raster object
size
positive integer giving the number of items to choose.
...
Additional argument: na.rm. If TRUE NA values are removed from random sample
extent
Extent. To limit regular sampling to the area within that box
cells
Logical. Also return sampled cell numbers (if asRaster==FALSE)
asRaster
Logical. If TRUE, a rasterLayer is returned, rather then the sampled values
corners
Logical. If TRUE, the extreme corner cells are always included. This makes for rather irregular sampling when n is small; but it can be useful when asRaster=TRUE, to maintain the same extent as the input RasterLayer

Value

  • A vector, matrix (if cells=TRUE; or for a multi-layered object), or RasterLayer (if asRaster=TRUE)

Details

With na.rm=TRUE, the returned sample may be smaller than requested

Examples

Run this code
r <- raster(system.file("external/test.grd", package="raster"))
 v <- sampleRegular(r, size=100)

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