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r.out.ascii(1grass)

r.out.ascii(1grass) GRASS User's Manual r.out.ascii(1grass)

NAME

r.out.ascii - Converts a raster map layer into a GRASS ASCII text file.

KEYWORDS

raster, export, output, ASCII, Surfer, Modflow, Lisflood

SYNOPSIS

r.out.ascii
r.out.ascii --help
r.out.ascii [-hsmli] input=name [output=name] [precision=integer] [width=integer] [null_value=string] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-h

Suppress printing of header information
-s

Write SURFER (Golden Software) ASCII grid
-m

Write MODFLOW (USGS) ASCII array
-l

Write LISFLOOD (EU) ASCII array
-i

Force output of integer values
--overwrite

Allow output files to overwrite existing files
--help

Print usage summary
--verbose

Verbose module output
--quiet

Quiet module output
--ui

Force launching GUI dialog

Parameters:

input=name [required]

Name of input raster map
output=name

Name for output ASCII grid map (use out=- for stdout)
precision=integer

Number of significant digits (floating point only)
width=integer

Number of values printed before wrapping a line (only SURFER or MODFLOW format)
null_value=string

String to represent null cell (GRASS grid only)
Default: *

DESCRIPTION

r.out.ascii converts a user-specified raster map layer (input=name) into an ASCII grid in a text file (output=name) suitable for export to other computer systems.

The GRASS program r.in.ascii can be used to perform the reverse function, converting an ASCII file in suitable format to GRASS raster map format.

To write a SURFER .grd ASCII GRID file (with reverted row order and different header) use the -s flag: 

r.out.ascii -s input=inname output=outname.grd [dp=value]
NULL data are coded to "1.70141e+038" for SURFER ASCII GRID files (ignoring the null= parameter).

To write a LISFLOOD .dem ASCII GRID file (with different header) use the -l flag: 

r.out.ascii -l input=inname output=outname.dem
NULL data output are set by the user at "-9999" in this case, see below: 
ncols		1514
nrows		2747
xllcorner	212236
yllcorner	2910116
cellsize	120
NODATA_value	-9999

NOTES

The output from r.out.ascii may be placed into a file by using the UNIX redirection mechanism; e.g.: 

r.out.ascii input=soils output=- > out.file

The output file out.file can then be printed or copied onto a CDROM or floppy disk for export purposes.

To export the raster values as x,y,z values of cell centers (one per line) use the r.out.xyz module.

SEE ALSO

r.in.ascii, r.in.gdal, r.out.bin, r.out.gdal, r.out.xyz

AUTHORS

Michael Shapiro, U.S. Army Construction Engineering Research Laboratory

Surfer support by Markus Neteler

SOURCE CODE

Available at: r.out.ascii source code (history)

Accessed: Thursday Jun 18 12:48:04 2026

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© 2003-2026 GRASS Development Team, GRASS 8.5.0 Reference Manual

GRASS 8.5.0