r.out.ascii(1)

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)

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

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