# sampleRandom

##### Random sample

Take a random sample from the cell values of a Raster* object (without replacement).

- Keywords
- spatial

##### Usage

```
# S4 method for Raster
sampleRandom(x, size, na.rm=TRUE, ext=NULL,
cells=FALSE, rowcol=FALSE, xy=FALSE, sp=FALSE, asRaster=FALSE, ...)
```

##### Arguments

- x
Raster* object

- size
positive integer giving the number of items to choose

- na.rm
logical. If

`TRUE`

(the default),`NA`

values are removed from random sample- ext
Extent object. To limit regular sampling to the area within the extent

- cells
logical. If

`TRUE`

, sampled cell numbers are also returned- rowcol
logical. If

`TRUE`

, sampled row and column numbers are also returned- xy
logical. If

`TRUE`

, coordinates of sampled cells are also returned- sp
logical. If

`TRUE`

, a SpatialPointsDataFrame is returned- asRaster
logical. If

`TRUE`

, a Raster* object is returned with random cells with values, all other cells with`NA`

- ...
Additional arguments as in

`writeRaster`

. Only relevant when`asRaster=TRUE`

##### Details

With argument `na.rm=TRUE`

, the returned sample may be smaller than requested

##### Value

A vector, matrix (if `cells=TRUE`

or `x`

is a multi-layered object), or a SpatialPointsDataFrame (if `sp=TRUE`

)

##### See Also

##### Examples

```
# NOT RUN {
r <- raster(system.file("external/test.grd", package="raster"))
sampleRandom(r, size=10)
s <- stack(r, r)
sampleRandom(s, size=5, cells=TRUE, sp=TRUE)
# }
```

*Documentation reproduced from package raster, version 3.1-5, License: GPL (>= 3)*