# sampleRegular

##### Regular sample

Take a systematic sample from a Raster* object.

- Keywords
- spatial

##### Usage

```
# S4 method for Raster
sampleRegular(x, size, ext=NULL, cells=FALSE, xy=FALSE, asRaster=FALSE,
sp=FALSE, useGDAL=FALSE, ...)
```

##### Arguments

- x
Raster object

- size
positive integer giving the number of items to choose.

- ext
Extent. To limit regular sampling to the area within that box

- cells
logical. Also return sampled cell numbers (if asRaster=FALSE)

- xy
logical. If

`TRUE`

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

`TRUE`

, a RasterLayer or RasterBrick is returned, rather than the sampled values- sp
logical. If

`TRUE`

, a SpatialPointsDataFrame is returned- useGDAL
logical. If

`TRUE`

, GDAL is used to sample in some cases. This is quicker, but can result in values for a different set of cells than when`useGDAL=FALSE`

. Only for rasters that are accessed via rgdal, and are not rotated. When`TRUE`

arguments`cells`

,`xy`

, and`sp`

are ignored (i.e.,`FALSE`

- ...
additional arguments. None implemented

##### Value

A vector (single layer object), matrix (multi-layered object; or if `cells=TRUE`

, or `xy=TRUE`

), Raster* object (if `asRaster=TRUE`

), or SpatialPointsDataFrame (if `sp=TRUE`

)

##### See Also

##### Examples

```
# NOT RUN {
r <- raster(system.file("external/test.grd", package="raster"))
v <- sampleRegular(r, size=100)
x <- sampleRegular(r, size=100, asRaster=TRUE)
# }
```

*Documentation reproduced from package raster, version 2.9-5, License: GPL (>= 3)*