`sampleRandom.Rd`

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

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

- 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`

With argument `na.rm=TRUE`

, the returned sample may be smaller than requested

A vector, matrix (if `cells=TRUE`

or `x`

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

)

```
r <- raster(system.file("external/test.grd", package="raster"))
sampleRandom(r, size=10)
#> [1] 461.2969 318.2996 351.8303 392.7534 492.7690 243.2765 440.3402 345.6403
#> [9] 515.7428 384.0551
s <- stack(r, r)
sampleRandom(s, size=5, cells=TRUE, sp=TRUE)
#> coordinates cell test.1 test.2
#> 1 (178700, 330180) 7608 418.1480 418.1480
#> 2 (179260, 329740) 8502 433.9139 433.9139
#> 3 (179620, 329980) 8031 312.8522 312.8522
#> 4 (180980, 332620) 2785 245.0019 245.0019
#> 5 (180940, 333020) 1984 392.7534 392.7534
```