brick: Create a RasterBrick object

In raster: Geographic Data Analysis and Modeling

Create a RasterBrick object

Description

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.

Usage

## 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.

Value

RasterBrick

See Also

raster

Examples

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

raster documentation built on Oct. 3, 2024, 1:08 a.m.