brick function

Create a RasterBrick object

A RasterBrick is a multi-layer raster object. They are typically created from a multi-layer (band) file; but they can also exist entirely in memory. They are similar to a RasterStack (that can be created with stack), but processing time should be shorter when using a RasterBrick. Yet they are less flexible as they can only point to a single file.

A RasterBrick can be created from RasterLayer objects, from a RasterStack, or from a (multi-layer) file. The can also be created from SpatialPixels*, SpatialGrid*, and Extent objects, and from a three-dimensional array. methods

## S4 method for signature 'character'
brick(x, ...)

## S4 method for signature 'RasterStack'
brick(x, values=TRUE, nl, filename='', ...) 

## S4 method for signature 'RasterBrick'
brick(x, nl, ...)

## S4 method for signature 'RasterLayer'
brick(x, ..., values=TRUE, nl=1, filename='') 

## S4 method for signature 'missing'
brick(nrows=180, ncols=360, xmn=-180, xmx=180, ymn=-90, ymx=90, nl=1, crs)

## S4 method for signature 'Extent'
brick(x, nrows=10, ncols=10, crs="", nl=1)

## S4 method for signature 'array'
brick(x, xmn=0, xmx=1, ymn=0, ymx=1, crs="", transpose=FALSE)

## S4 method for signature 'SpatialGrid'
brick(x)

## S4 method for signature 'SpatialPixels'
brick(x)

Arguments

• x: character (filename, see Details); Raster* object; missing; array; SpatialGrid*; SpatialPixels*; Extent; or list of Raster* objects. Supported file types are the 'native' raster package format and those that can be read via GDAL, and NetCDF files (see details)
• ...: see Details
• values: logical. If TRUE, the cell values of 'x' are copied to the RasterBrick object that is returned
• nl: integer > 0. How many layers should the RasterBrick have?
• filename: character. Filename if you want the RasterBrick to be saved on disk
• nrows: integer > 0. Number of rows
• ncols: integer > 0. Number of columns
• xmn: minimum x coordinate (left border)
• xmx: maximum x coordinate (right border)
• ymn: minimum y coordinate (bottom border)
• ymx: maximum y coordinate (top border)
• crs: character or object of class CRS. PROJ4 type description of a Coordinate Reference System (map projection). If this argument is missing, and the x coordinates are within -360 .. 360 and the y coordinates are within -90 .. 90, "+proj=longlat +datum=WGS84" is used
• transpose: if TRUE, the values in the array are transposed

Details

If x is a RasterLayer, the additional arguments can be used to pass additional Raster* objects.

If there is a filename argument, the additional arguments are as for writeRaster.

If x represents a filename there is the following additional argument:

native: logical. If TRUE (not the default), reading and writing of IDRISI, BIL, BSQ, BIP, and Arc ASCII files is done with native (raster package) drivers, rather then via GDAL.

In addition, if x is a NetCDF filename there are the following additional arguments:

varname: character. The variable name (e.g. 'altitude' or 'precipitation'. If not supplied and the file has multiple variables are a guess will be made (and reported))

lvar: integer > 0 (default=3). To select the 'level variable' (3rd dimension variable) to use, if the file has 4 dimensions (e.g. depth instead of time)

level: integer > 0 (default=1). To select the 'level' (4th dimension variable) to use, if the file has 4 dimensions, e.g. to create a RasterBrick of weather over time at a certain height.

dims: integer vector to indicated the order of the dimensions. Default is dims=c(1,2,3) (rows, cols, time).

To use NetCDF files the ncdf4 package needs to be available. It is assumed that these files follow, or are compatible with the CF-1 convention.

Returns

RasterBrick

See Also

raster

Examples

b <- brick(system.file("external/rlogo.grd", package="raster"))
b
nlayers(b)
names(b)
extract(b, 870)