NAME
r.external.out - Redirects raster output to file utilizing GDAL library rather than storing in GRASS raster format.
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, COG, NITF, HFA, ELAS, AAIGrid, DTED, PNG, JPEG, MEM, GIF, FITS, XPM, BMP, PCIDSK, PCRaster, ILWIS, SGI, SRTMHGT, Leveller, Terragen, GMT, netCDF, HDF4Image, ISIS3, ISIS2, PDS4, VICAR, ERS, JP2OpenJPEG, FIT, GRIB, RMF, WMS, RST, INGR, GSAG, GSBG, GS7BG, R, KMLSUPEROVERLAY, WEBP, PDF, Rasterlite, MBTiles, CALS, WMTS, MRF, PNM, PAux, MFF, MFF2, BT, LAN, IDA, LCP, GTX, NTv2, CTable2, KRO, ROI_PAC, RRASTER, BYN, ARG, USGSDEM, BAG, NWT_GRD, ADRG, BLX, EPSILON, PostGISRaster, SAGA, XYZ, HF2, JPEGLS, ZMap, SIGDEM, GPKG, NGW, ENVI, EHdr, ISCE
- options=string[,string,...]
- Creation options
r.external.out instructs GRASS GIS to write subsequently generated
raster maps as data files (e.g. GeoTIFF) using GDAL instead of storing them
in GRASS raster format in the current mapset.
Any new raster map is immediately written out through GDAL as a file.
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.
The module
r.external.out is used to write out processing results
directly in GeoTIFF format (any GDAL supported format can be used here):
# define output directory for files resulting from GRASS calculation(s)
# and target format:
mkdir $HOME/gisoutput/
# hint: the create options are not mandatory
r.external.out directory=$HOME/gisoutput/ format="GTiff" option="BIGTIFF=YES,COMPRESS=DEFLATE"
# prepare sample analysis
g.region raster=elevation -p
# perform GRASS calculation (here: filter by height, write > 120m, NULL otherwise)
# this will store the output map directly as GeoTIFF, so we use .tif extension:
r.mapcalc "elev_filt.tif = if(elevation > 120.0, elevation, null() )"
# ...the "elev_filt.tif" is immediately written.
# cease GDAL output connection and turn back to write out GRASS raster files:
r.external.out -r
# verify resulting file
gdalinfo $HOME/gisoutput/elev_filt.tif
The module
r.external.out can be used along with
r.external to process external geodata in GRASS
while writing out the results directly in GeoTIFF:
# register GeoTIFF file to be used in current mapset:
r.external input=terra_lst1km20030314.LST_Day.tif output=modis_celsius
# define output directory for files resulting from GRASS calculation:
r.external.out directory=$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
GDAL Pages:
https://gdal.org/
r.in.gdal,
r.out.gdal,
r.external
Glynn Clements
SOURCE CODE
Available at:
r.external.out source code
(history)
Latest change: Friday Oct 25 16:16:09 2024 in commit: 5b94314a82de7e9c78fd6044659ea9d6c2323edb
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GRASS Development Team,
GRASS GIS 8.5.0dev Reference Manual