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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:


Suppress printing of header information

Write SURFER (Golden Software) ASCII grid

Write MODFLOW (USGS) ASCII array

Write LISFLOOD (EU) ASCII array

Force output of integer values

Allow output files to overwrite existing files

Print usage summary

Verbose module output

Quiet module output

Force launching GUI dialog

Parameters:


Name of input raster map

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

Number of significant digits (floating point only)

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

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)

Latest change: Sunday Oct 05 01:26:10 2025 in commit: 14fd3ee61b78346fc901c0aa1d874c83c16cc51a

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

GRASS 8.5.0