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.
# 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="", nl=1) # S4 method for array brick(x, xmn=0, xmx=1, ymn=0, ymx=1, crs="", transpose=FALSE) # S4 method for SpatialGrid brick(x) # S4 method for SpatialPixels brick(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)
TRUE, the cell values of '
x' are copied to the RasterBrick object that is returned
integer > 0. How many layers should the RasterBrick have?
character. Filename if you want the RasterBrick to be saved on disk
integer > 0. Number of rows
integer > 0. Number of columns
minimum x coordinate (left border)
maximum x coordinate (right border)
minimum y coordinate (bottom border)
maximum y coordinate (top border)
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
TRUE, the values in the array are transposed
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
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.
b <- brick(system.file("external/rlogo.grd", package="raster")) b #> class : RasterBrick #> dimensions : 77, 101, 7777, 3 (nrow, ncol, ncell, nlayers) #> resolution : 1, 1 (x, y) #> extent : 0, 101, 0, 77 (xmin, xmax, ymin, ymax) #> crs : +proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs #> source : rlogo.grd #> names : red, green, blue #> min values : 0, 0, 0 #> max values : 255, 255, 255 #> nlayers(b) #>  3 names(b) #>  "red" "green" "blue" extract(b, 870) #> red green blue #> [1,] 149 149 137