raster (version 1.9-44)

sampleRegular: Regular sample

Description

Take a systematic sample from a Raster* object.

Usage

sampleRegular(x, size, ext=NULL, cells=FALSE, asRaster=FALSE, useGDAL=FALSE)

Arguments

x

a 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)

asRaster

Logical. If TRUE, a RasterLayer or RasterBrick is returned, rather then the sampled values

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. Only for rasters that are accessed via rgdal, are not rotated, and when cells=FALSE.

Value

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

See Also

sampleRandom

Examples

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