GRASS GIS manual: r.external.out

Note: A new GRASS GIS stable version has been released: GRASS GIS 7.4, available here.
Updated manual page: here

NAME

r.external.out - Defines raster output format utilizing GDAL library.

KEYWORDS

raster, export, output, external

SYNOPSIS

r.external.out

r.external.out --help

r.external.out [-frp] directory=path [extension=string] format=string [options=string[,string,...]] [--help] [--verbose] [--quiet] [--ui]

Flags:

-f: List supported formats and exit
-r: Cease using GDAL and revert to native output
-p: Print current status
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

directory=path [required]: Name of output directory
extension=string: Extension for output files
format=string [required]: Format of output files; Options: VRT, GTiff, NITF, HFA, ELAS, AAIGrid, DTED, PNG, JPEG, MEM, GIF, XPM, BMP, PCIDSK, PCRaster, ILWIS, SGI, SRTMHGT, Leveller, Terragen, GMT, netCDF, HDF4Image, ISIS2, ERS, JPEG2000, FIT, RMF, WMS, RST, INGR, GSAG, GSBG, GS7BG, R, PNM, ENVI, EHdr, PAux, MFF, MFF2, BT, LAN, IDA, GTX, NTv2, CTable2, ARG, USGSDEM, ADRG, BLX, Rasterlite, EPSILON, PostGISRaster, SAGA, KMLSUPEROVERLAY, XYZ, HF2, PDF, WEBP, ZMap
options=string[,string,...]: Creation options

DESCRIPTION
NOTES
EXAMPLE
REFERENCES
SEE ALSO
AUTHOR

DESCRIPTION

r.external.out instructs GRASS to write raster maps as data files (e.g. GeoTIFF) using GDAL.

A relative directory path (parameter directory) is interpreted relative to the current mapset directory, not the current directory where the command was launched. An unspecified or empty directory (which will occur if the user passes a simple filename for output) results in the output file being placed in the "gdal/" subdirectory of the current mapset directory.

EXAMPLE

The module r.external.out can be used along with r.external to process external geodata in GRASS while writing out the results directly in GeoTIFF:

# register GeoTIFF file to be used in current mapset:
r.external input=terra_lst1km20030314.LST_Day.tif output=modis_celsius

# define output directory for files resulting from GRASS calculation:
r.external.out directory=$HOME/gisoutput/ format="GTiff"

# perform GRASS calculation (here: extract pixels > 20 deg C)
# this stores the output map directly as GeoTIFF:
r.mapcalc "warm.tif = if(modis_celsius > 20.0, modis_celsius, null() )"

# cease GDAL output connection and turn back to write GRASS raster files:
r.external.out -r

# now use the resulting file elsewhere
gdalinfo $HOME/gisoutput/warm.tif