R: Regular sample

sampleRegular {raster} | R Documentation

## Regular sample

### Description

Take a systematic sample from a Raster* object.

### Usage

    ## S4 method for signature '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 then 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

`sampleRandom`, sampleStratified

### Examples

     r <- raster(system.file("external/test.grd", package="raster"))
     v <- sampleRegular(r, size=100)
     x <- sampleRegular(r, size=100, asRaster=TRUE)

[Package raster version 2.6-7 Index]