create_blank_raster: Create an empty raster and header.
In spatial.tools: R Functions for Working with Spatial Data

Description Usage Arguments Details Value Author(s) See Also Examples

This function creates an arbitrarily large raster as a flat binary file with (optionally) a proper header for use with other functions. This should create the blank files very quickly, as it is using some OS tricks to carve out a block of space rather than writing a bunch of 0s to disk sequentially.

create_blank_raster(
  filename = NULL,
  format = "raster",
  datatype = "FLT8S",
  bandorder = "BSQ",
  nrow = NULL,
  ncol = NULL,
  nlayers = NULL,
  create_header = TRUE,
  reference_raster = NULL,
  return_filename = TRUE,
  additional_header = NULL,
  overwrite = FALSE,
  verbose = FALSE
)

`filename`	Character. The output base filename of the blank file. Will use tempfile() if nothing is provided.
`format`	Character. Output format. Currently only supports "raster".
`datatype`	Character. Output number type. See ?dataType. Default is "FLT8S".
`bandorder`	Character. Output band interleave. Currently only supports "BSQ".
`nrow`	Numeric. Number of rows of the output raster. Defaults to nrow(reference_raster).
`ncol`	Numeric. Number of columns of the output raster. Defaults to ncol(reference_raster).
`nlayers`	Numeric. Number of layers of the output raster Defaults to nlayer(reference_raster).
`create_header`	Logical. Create a properly formatted header for the blank file?
`reference_raster`	Raster*. Reference raster to derive other information, e.g. resolution, projection, datum.
`return_filename`	Logical. Return filename of the binary file (if TRUE, default) or the Raster* itself (if FALSE).
`additional_header`	Character. Create additional output headers for use with other GIS systems (see `hdr`). Set to NULL (default) to suppress.
`overwrite`	Logical. Overwrite an existing file with the same name?
`verbose`	Logical. Enable verbose execution? Default is FALSE.

create_blank_raster is designed to quickly create a binary file of the appropriate size using tricks with seek()/writeBin(). A large file can be created in a fraction of a second using this function. This file could, for example, be used with mmap to realize asynchronous or, OS permitting, parallel writes to a single file. Note that setMinMax are NOT performed on the output file (to save time), so on some systems you may see a warning.

Binary files of this type are used by a number of raster formats, including raster and ENVI.

A character vector (return_filename==TRUE) or as Raster* object (return_filename==TRUE)

Jonathan A. Greenberg

hdr

## Not run:  
tahoe_highrez <- brick(system.file("external/tahoe_highrez.tif", package="spatial.tools"))
test_blank_file <- create_blank_raster(reference_raster=tahoe_highrez)
file.info(test_blank_file)
test_blank_raster <- create_blank_raster(reference_raster=tahoe_highrez,return_filename=FALSE)
test_blank_raster

## End(Not run)