brick: 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 character
brick(x, ...)
# S4 method for RasterStack
brick(x, values=TRUE, nl, filename='', ...) 
# S4 method for RasterBrick
brick(x, nl, ...)
# S4 method for RasterLayer
brick(x, ..., values=TRUE, nl=1, filename='') 
# S4 method for missing
brick(nrows=180, ncols=360, xmn=-180, xmx=180, ymn=-90, ymx=90, nl=1, crs)
# S4 method for Extent
brick(x, nrows=10, ncols=10, crs=NA, nl=1)
# S4 method for array
brick(x, xmn=0, xmx=1, ymn=0, ymx=1, crs=NA, transpose=FALSE)
# S4 method for big.matrix
brick(x, template, filename='', ...)
# S4 method for SpatialGrid
brick(x)
# S4 method for SpatialPixels
brick(x)

Arguments

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 rgdal (see readGDAL), 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

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 withing -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

template

Raster* object used to set the extent, number of rows and columns and CRS

Value

RasterBrick

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. The big.matrix most have rows representing cells and columns representing layers.

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 rgdal.

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.

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.

Examples

Run this code

# NOT RUN {
b <- brick(system.file("external/rlogo.grd", package="raster"))
b
nlayers(b)
names(b)
extract(b, 870)
# }