variables(1grass) GRASS GIS User's Manual variables(1grass)
GRASS variables and environment variables
There are two types of variables:
• shell environment variables,
• GRASS gisenv variables.
There are a number of shell environment variable groups:
• variables for rendering
• variables for internal use
Note: Any setting which needs to be modifiable by a GRASS module (e.g.
MONITOR by d.mon) has to be a GRASS gisenv variable.
Setting shell environment variables
Setting shell environment variables depends on the shell being used:
Bash:
export VARIABLE=value
Csh:
setenv VARIABLE value
Cmd.exe (Windows):
set VARIABLE=value
To set up shell environment variables permanently:
• To get personal BASH shell definitions (aliases, color listing
option, ...) into GRASS, store them in:
$HOME/.grass7/bashrc
• To get personal CSH shell definitions (aliases, color listing
option, ...) into GRASS, store them in:
$HOME/.grass7/cshrc
Setting GRASS gisenv variables
Use g.gisenv within GRASS. This permanently predefines GRASS variables
in the $HOME/.grass7/rc file after the current GRASS session is closed.
Usage:
g.gisenv set="VARIABLE=VALUE"
It looks unusual with two equals signs, but g.gisenv serves dual duty
for getting and setting GRASS variables.
If the user just specifies a variable name, it defaults to get mode.
For example:
g.gisenv MAPSET
PERMANENT
List of selected (GRASS related) shell environment variables
[ To be set from the terminal shell or startup scripts ]
GISBASE
directory where GRASS lives. This is set automatically by the
startup script.
GISRC
name of $HOME/.grass7/rc file. Defines the system wide value when
starting a GRASS session. Within a GRASS session, a temporary copy
of this file will be used.
GRASS_ADDON_PATH
[grass startup script, g.extension]
specifies additional path(s) containing local and/or custom GRASS
modules extra to the standard distribution.
GRASS_ADDON_BASE
[grass startup script]
allows specifying additional GISBASE for local GRASS modules (nor-
mally installed as GRASS Addons by g.extension module) extra to
standard distribution. The default on GNU/Linux is
$HOME/.grass7/addons, on MS Windows $APPDATA\GRASS7\addons.
GRASS_ADDON_ETC
[libgis, g.findetc]
specify paths where support files (etc/) may be found external to
standard distribution.
GRASS_BATCH_JOB
defines the name (path) of a shell script to be processed as batch
job.
GRASS_COMPRESSOR
[libraster]
the compression method for new raster maps can be set with the en-
vironment variable GRASS_COMPRESSOR. Supported methods are RLE,
ZLIB, LZ4, BZIP2, and ZSTD. The default is ZSTD if available, oth-
erwise ZLIB, which can be changed with e.g. GRASS_COMPRESSOR=ZSTD,
granted that GRASS has been compiled with the requested compressor.
Compressors that are always available are RLE, ZLIB, and LZ4. The
compressors BZIP2 and ZSTD must be enabled when configuring GRASS
for compilation.
GRASS_DB_ENCODING
[various modules, wxGUI]
encoding for vector attribute data (utf-8, ascii, iso8859-1,
koi8-r)
GIS_ERROR_LOG
If set, GIS_ERROR_LOG should be the absolute path to the log file
(a relative path will be interpreted relative to the process’ cwd,
not the cwd at the point the user set the variable). If not set,
$HOME/GIS_ERROR_LOG is used instead. The file will only be used if
it already exists.
GRASS_ERROR_MAIL
set to any value to send user mail on an error or warning that hap-
pens while stderr is being redirected.
GRASS_FONT
[display drivers]
specifies the font as either the name of a font from $GIS-
BASE/etc/fontcap (or alternative fontcap file specified by
GRASS_FONT_CAP), or alternatively the full path to a FreeType font
file.
GRASS_ENCODING
[display drivers]
the encoding to be assumed for text which is drawn using a freetype
font; may be any encoding know to iconv.
GRASS_FONT_CAP
[g.mkfontcap, d.font, display drivers]
specifies an alternative location (to $GISBASE/etc/fontcap) for the
font configuration file.
GRASS_FULL_OPTION_NAMES
[parser]
Generates a warning if GRASS_FULL_OPTION_NAMES is set (to anything)
and a found string is not an exact match for the given string.
GRASS_GUI
either text (text user interface), gtext (text user interface with
GUI welcome screen), or gui (graphical user interface) to define
non-/graphical startup. Can also specify the name of the GUI to
use, e.g. wxpython (wxGUI). Also exists as a GRASS gisenv variable
(see below). If this shell variable exists at GRASS startup, it
will determine the GUI used. If it is not defined startup will de-
fault to the last GUI used.
GRASS_HTML_BROWSER
[init.sh, wxgui]
defines name of HTML browser. For most platforms this should be an
executable in your PATH, or the full path to an executable.
Mac OS X runs applications differently from the CLI. Therefore,
GRASS_HTML_BROWSER should be the application’s signature, which is
a domain-like name, just reversed, i.e. com.apple.Safari. To find
an application’s signature, type the following in a Terminal (fill
in the path to the application you are interested in, for example:
/Applications/Safari.app):
grep -A 1 "CFBundleIdentifier" /path/to/application.app/Con-
tents/Info.plist
The signature is the <string> following the <key>, without the
bracketing <string> tags.
GRASS_INT_ZLIB
[libraster]
if the environment variable GRASS_INT_ZLIB exists and has the value
0, new compressed integer (CELL type) raster maps will be com-
pressed using RLE compression.
If the variable doesn’t exist, or the value is non-zero, zlib com-
pression will be used instead. Such rasters will have a compressed
value of 2 in the cellhd file.
Obviously, decompression is controlled by the raster’s compressed
value, not the environment variable.
GRASS_ZLIB_LEVEL
[libgis]
if the environment variable GRASS_ZLIB_LEVEL exists and its value
can be parsed as an integer, it determines the compression level
used when new compressed raster maps are compressed using zlib com-
pression. This applies to all raster map types (CELL, FCELL,
DCELL).
Valid zlib compression levels are -1 to 9. The GRASS_ZLIB_LEVEL=-1
corresponds to the zlib default value (equivalent to
GRASS_ZLIB_LEVEL=6). Often GRASS_ZLIB_LEVEL=1 gives the best com-
promise between speed and compression.
If the variable doesn’t exist, or the value cannot be parsed as an
integer, zlib’s default compression level 6 will be used.
GRASS_MESSAGE_FORMAT
[various modules, wxGUI]
it may be set to either
• standard - sets percentage output and message formatting style
to standard formatting,
• gui - sets percentage output and message formatting style to
GUI formatting,
• silent - disables percentage output and error messages,
• plain - sets percentage output and message formatting style to
ASCII output without rewinding control characters.
GRASS_MOUSE_BUTTON
[various modules]
swaps mouse buttons for two-button or left-handed mice. Its value
has three digits 1, 2, and 3, which represent default left, middle,
and right buttons respectively. Setting to 132 will swap middle and
right buttons. Note that this variable should be set before a dis-
play driver is initialized (e.g., d.mon x0).
GRASS_PAGER
[various modules]
it may be set to either less, more, or cat.
GRASS_PERL
[used during install process for generating man pages]
set Perl with path.
GRASS_PROXY
[used during addon install/reinstall process for generating man
pages (download commit from GitHub API server and remote mod-
ules.xml file)]
set the proxy with: GRASS_PROXY="http=<value>,ftp=<value>".
GRASS_SKIP_MAPSET_OWNER_CHECK
By default it is not possible to work with MAPSETs that are not
owned by current user. Setting this variable to any non-empty value
allows the check to be skipped.
GRASS_SH
[shell scripts on Windows]
path to bourne shell interpreter used to run shell scripts.
GRASS_SIGSEGV_ON_ERROR
Raise SIGSEGV if an error occurs]
This variable can be set for debugging purpose. The call of G_fa-
tal_error() will end in a segmentation violation. GDB can be used
to trace the source of the error.
GRASS_PYTHON
[wxGUI, Python Ctypes]
set to override Python executable.
On Mac OS X this should be the pythonw executable for the wxGUI to
work.
GRASS_VECTOR_LOWMEM
[vectorlib]
If the environment variable GRASS_VECTOR_LOWMEM exists, memory con-
sumption will be reduced when building vector topology support
structures. Recommended for creating large vectors.
GRASS_VECTOR_OGR
[vectorlib, v.external.out]
If the environment variable GRASS_VECTOR_OGR exists and vector out-
put format defined by v.external.out is PostgreSQL, vector data is
written by OGR data provider even the native PostGIS data provider
is available.
GRASS_VECTOR_EXTERNAL_IMMEDIATE
[vectorlib, v.external.out]
If the environment variable GRASS_VECTOR_EXTERNAL_IMMEDIATE exists
and vector output format defined by v.external.out is non-native,
vector features are written to output external datasource immedi-
ately. By default, the vector library writes output data to a tem-
porary vector map in native format and when closing the map, the
features are transferred to output external datasource. Note: if
output vector format is topological PostGIS format, then the vector
library writes features immediately to output database (in this
case GRASS_VECTOR_EXTERNAL_IMMEDIATE is ignored).
GRASS_VECTOR_EXTERNAL_IGNORE
[vectorlib]
If the environment variable GRASS_VECTOR_EXTERNAL_IGNORE exists,
output vector format defined by v.external.out is ignored. The for-
mat is always native.
GRASS_VECTOR_TEMPORARY
[vectorlib]
If the environment variable GRASS_VECTOR_TEMPORARY exists, GRASS
vector library will operate on temporary vector maps. New vector
maps will be created in temporary directory (see GRASS_VECTOR_TM-
PDIR_MAPSET variable), existing vector maps will be read (if found)
also from this directory. It may be set to either:
• keep - the temporary vector map is not deleted when closing the
map.
• move - the temporary vector map is moved to the current mapset
when closing the map.
• delete - the temporary vector map is deleted when closing the
map.
Default value is keep. Note that temporary vector maps are not visible
to the user via g.list or wxGUI. They are used internally by the GRASS
modules and deleted automatically when GRASS session is quited.
GRASS_VECTOR_TMPDIR_MAPSET
[vectorlib]
By default GRASS temporary directory is located in $LOCA-
TION/$MAPSET/.tmp/$HOSTNAME. If GRASS_VECTOR_TMPDIR_MAPSET is set
to ’0’, the temporary directory is located in TMPDIR (environmental
variable defined by the user or GRASS initialization script if not
given).
Important note: This variable is currently used only in vector li-
brary. In other words the variable is ignored by raster or raster3d
library.
GRASS_VECTOR_TOPO_DEBUG
[vectorlib, v.generalize]
If the environment variable GRASS_VECTOR_TOPO_DEBUG exists, v.gen-
eralize runs in extremely slow debug mode.
GRASS_WXBUNDLED
[wxGUI]
set to tell wxGUI that a bundled wxPython will be used.
When set, the wxGUI will not check the wxPython version, as this
function is incompatible with a bundled wxPython. It is up to the
packager to make sure that a compatible wxPython version is bun-
dled.
GRASS_WXVERSION
[wxGUI]
set to tell wxGUI which version of wxPython to use.
When set, the wxGUI will select the given wxPython version. It’s
useful when multiple versions of wxPython are installed and the
user wants to run wxGUI with non-default wxPython version.
GRASS_XTERM
[lib/init/grass-xterm-wrapper, lib/init/grass-xterm-mac]
set to any value (e.g. rxvt, aterm, gnome-terminal, konsole) to
substitute ’x-terminal-emulator’ or ’xterm’. The Mac OS X app
startup defaults to an internal ’$GISBASE/etc/grass-xterm-mac’,
which emulates the necessary xterm functionality in Terminal.app.
GRASS_UI_TERM
set to any value to use the terminal based parser.
GRASS_VERSION
reports the current version number (used by R-stats interface etc);
should not be changed by user.
GRASS_NO_GLX_PBUFFERS
[nviz]
set to any value to disable the use of GLX Pbuffers.
GRASS_NO_GLX_PIXMAPS
[nviz]
Set to any value to disable the use of GLX Pixmaps.
OMP_NUM_THREADS
[OpenMP]
If OpenMP support is enabled this limits the number of threads.
The default is set to the number of CPUs on the system. Setting to
’1’ effectively disables parallel processing.
TMPDIR, TEMP, TMP
[Various GRASS GIS commands and wxGUI]
The default wxGUI temporary directory is chosen from a platform-de-
pendent list, but the user can control the selection of this direc-
tory by setting one of the TMPDIR, TEMP or TMP environment vari-
ables Hence the wxGUI uses $TMPDIR if it is set, then $TEMP, other-
wise /tmp.
List of selected GRASS environment variables for rendering
[ In addition to those which are understood by specific GRASS display
drivers, the following variables affect rendering. ]
GRASS_RENDER_IMMEDIATE
tells the display library which driver to use; possible values:
cairo, png, ps, html or default.
Default display driver is cairo (if available) otherwise png.
GRASS_RENDER_WIDTH
defines the width of output image (default is 640).
GRASS_RENDER_HEIGHT
defines the height of output image (default is 480).
GRASS_RENDER_FILE
the name of the resulting image file.
GRASS_RENDER_FRAME
contains 4 coordinates, top,bottom,left,right (pixel values) with
respect to the top left corner of the output image, defining the
initial frame.
GRASS_RENDER_LINE_WIDTH
defines default line width.
GRASS_RENDER_TEXT_SIZE
defines default text size.
GRASS_RENDER_COMMAND
external command called by display library to render data (see ex-
ample in display drivers page for details).
Currently only Python scripts are supported. For specific
driver-related variables see:
• Cairo display driver
• PNG display driver
• PS (Postscript) display driver
• HTML display driver
List of selected internal GRASS environment variables
[ These variables are intended for internal use only by the GRASS soft-
ware to facilitate communication between the GIS engine, GRASS scripts,
and the GUI. The user should not set these in a GRASS session. They
are meant to be set locally for specific commands. ]
GRASS_OVERWRITE
[all modules]
toggles map overwrite.
• 0 - maps are protected (default),
• 1 - maps with identical names will be overwritten.
This variable is automatically created by g.parser so that the --over-
write option will be inherited by dependent modules as the script runs.
Setting either the GRASS_OVERWRITE environment variable or the OVER-
WRITE gisenv variable detailed below will cause maps with identical
names to be overwritten.
GRASS_VERBOSE
[all modules]
toggles verbosity level
• -1 - complete silence (also errors and warnings are discarded)
• 0 - only errors and warnings are printed
• 1 - progress and important messages are printed (percent com-
plete)
• 2 - all module messages are printed
• 3 - additional verbose messages are printed
This variable is automatically created by g.parser so that the --ver-
bose or --quiet flags will be inherited by dependent modules as the
script runs.
GRASS_REGION
[libgis]
override region settings, separate parameters with a ";". Format is
the same as in the WIND region settings file. Otherwise use is the
same as WIND_OVERRIDE.
WIND_OVERRIDE
[libgis]
it causes programs to use the specified named region (created with
e.g. g.region save=...) to be used as the current region, instead
of the region from the WIND file.
This allows programs such as the GUI to run external commands on an
alternate region without having to modify the WIND file then change
it back afterwards.
List of selected GRASS gisenv variables
[ Use g.gisenv to get/set/unset/change them ]
DEBUG
[entire GRASS]
sets level of debug message output (0: no debug messages)
g.gisenv set=DEBUG=0
WX_DEBUG
[wxGUI]
sets level of debug message output for wxGUI (0: no debug messages,
1-5 debug levels)
GISDBASE
initial database
GIS_LOCK
lock ID to prevent parallel GRASS use,
process id of the start-up shell script
GUI
See GRASS_GUI environmental variable for details.
LOCATION
full path to location directory
LOCATION_NAME
initial location name
MAPSET
initial mapset
MEMORYMB
[entire GRASS with focus on raster related data processing]
sets the maximum memory to be used (in MB), i.e. the cache size for
raster rows
# set to 6 GB (default: 300 MB)
g.gisenv set="MEMORYMB=6000"
OVERWRITE
[all modules]
toggles map overwrite.
• 0 - maps are protected (default),
• 1 - maps with identical names will be overwritten.
This variable is automatically created by g.parser so that the --over-
write option will be inherited by dependent modules as the script runs.
Setting either the GRASS_OVERWRITE environment variable or the OVER-
WRITE gisenv variable detailed below will cause maps with identical
names to be overwritten.
GRASS-related Files
$HOME/.grass7/rc
stores the GRASS gisenv variables (not shell environment variables)
$HOME/.grass7/bashrc
stores the shell environment variables (Bash only)
$HOME/.grass7/env.bat
stores the shell environment variables (MS Windows only)
$HOME/.grass7/login
stores the DBMI passwords in this hidden file. Only the file owner
can access this file.
$HOME/GIS_ERROR_LOG
if this file exists then all GRASS error and warning messages are
logged here. Applies to current user. To generate the file, use:
touch $HOME/GIS_ERROR_LOG
See also GIS_ERROR_LOG variable. Note: On MS Windows the files are
stored in %APPDATA%.
SEE ALSO
g.gisenv, g.parser
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