grass7(1) GRASS GIS User's Manual grass7(1)
GRASS startup program
SYNOPSIS
grass78 [-h | -help | --help] [-v | --version] | [-c | -c geofile | -c
EPSG:code[:datum_trans]] | -e | -f | [--text | --gtext | --gui] |
--config | --tmp-location [[[<GISDBASE>/]<LOCATION>/] <MAPSET>] [--exec
EXECUTABLE]
Flags:
-h | -help | --help
Prints a brief usage message and exits
-v | --version
Prints the version of GRASS and exits
-c
Creates new GRASS unprojected location in specified GISDBASE
-c geofile
Creates new GRASS projected location in specified GISDBASE based on
georeferenced file
-c EPSG:code
Creates new GRASS projected location in specified GISDBASE with
given EPSG code
-c EPSG:code:datum_trans
Creates new GRASS projected location in specified GISDBASE with
given EPSG code and datum transform parameters
-e
Exit after creation of location or mapset. Only with -c flag
-f
Forces removal of .gislock if exists (use with care!). Only with
--text flag
--text
Indicates that Text-based User Interface should be used (skip wel-
come screen)
--gtext
Indicates that Text-based User Interface should be used (show wel-
come screen)
--gui
Indicates that Graphical User Interface (wxGUI) should be used
--config
Prints GRASS configuration parameters (options: arch, build, com-
piler, date, path, revision, svn_revision, version)
--exec EXECUTABLE
Execute GRASS module or script. The provided executable will be ex-
ecuted in a GRASS GIS non-interactive session.
--tmp-location
Run using a temporary location which is created based on the given
coordinate reference system and deleted at the end of the execution
(use with the --exec flag). The active mapset will be the PERMA-
NENT mapset.
Parameters:
GISDBASE
Initial database directory which should be a fully qualified path
(e.g., /usr/local/share/grassdata)
LOCATION
Initial location directory which is a subdirectory of GISDBASE
MAPSET
Initial mapset directory which is a subdirectory of LOCATION Note:
These parameters must be specified in one of the following ways:
MAPSET
LOCATION/MAPSET
GISDBASE/LOCATION/MAPSET
DESCRIPTION
This command is used to launch GRASS GIS. It will parse the command
line arguments and then initialize GRASS for the user. Since GRASS mod-
ules require a specific environment, this program must be called before
any other GRASS module can run. The command line arguments are optional
and provide the user with a method to indicate the desired user inter-
face, as well as the desired mapset to work on.
The startup program will remember both the desired user interface and
mapset. Thus, the next time the user runs GRASS, typing grass78 (with-
out any options) will start GRASS with the previous settings for the
user interface and mapset selected.
If you specify a graphical user interface (--gui) the grass78 program
will try to verify that the system you specified exists and that you
can access it successfully. If any of these checks fail then grass78
will automatically switch back to the text user interface mode.
FLAGS
The flag --config option prints GRASS GIS configuration and version pa-
rameters, with the options:
• arch: system architecture (e.g., x86_64-pc-linux-gnu)
• build: (e.g., ./configure --with-cxx --enable-largefile
--with-proj [...])
• compiler: (e.g., gcc)
• date: (e.g., 2020-04-24T14:49:27+00:00)
• path: (e.g., /usr/lib64/grass78)
• revision: (e.g., 54aa6fb87)
• svn_revision: (e.g., 4aa6fb87)
• version: (e.g., 7.8.3)
SAMPLE DATA
The GRASS GIS project provides several free sample geospatial datasets
as ready-to-use locations. They are available to download at
https://grass.osgeo.org/download/sample-data/. The "North Carolina
data set" is a modern package of geospatial data from North Carolina
(USA), and it includes raster, vector, LiDAR and satellite data. This
is the most extensively used data set in the documentation and the ex-
amples throughout the user manual pages are based upon it.
ENVIRONMENT VARIABLES
A number of environment variables are available at GRASS startup to as-
sist with automation and customization. Most users will not need to
bother with these.
In addition to these shell environment variables GRASS maintains a num-
ber of GIS environment variables in the $HOME/.grass7/rc file. User
changes to this file will be read during the next startup of GRASS. If
this file becomes corrupted the user may edit it by hand or remove it
to start afresh. See the list of implemented GRASS variables for more
information. The rest of this help page will only consider shell envi-
ronment variables.
Note that you will need to set these variables using the appropriate
method required for the UNIX shell that you use (e.g. in a Bash shell
you must export the variables for them to propagate).
User Interface Environment Variable
The grass78 program will check for the existence of an environment
variable called GRASS_GUI which indicates the type of user interface
for GRASS to use. If this variable is not set when grass78 is run, then
it will be created and then saved in the $HOME/.grass7/rc file for the
next time GRASS is run. It can be set to text, gtext or gui.
There is an order of precedence in the way grass78 determines the user
interface to use. The following is the hierarchy from highest prece-
dence to lowest.
1 Command line argument
2 Environment variable GRASS_GUI
3 Value set in $HOME/.grass7/rc (GUI)
4 Default value - gui
Python Environment Variables
If you choose to use wxGUI interface, then the GRASS_PYTHON environment
variable can be used to override your system default python command.
Suppose for example your system has Python 3.6 installed and you in-
stall a personal version of the Python 3.7 binaries under $HOME/bin.
You can use the above variables to have GRASS use the Python 3.7 bina-
ries instead.
GRASS_PYTHON=python3.7
Addon Path to Extra User Scripts
This environment variable allows the user to extend the GRASS program
search paths to include locally developed/installed GRASS modules or
user scripts.
GRASS_ADDON_PATH=/usr/mytools
GRASS_ADDON_PATH=/usr/mytools:/usr/local/othertools
In this example above path(s) would be added to the standard GRASS path
environment.
Addon Base for Extra Local GRASS Addon Modules
This environment variable allows the user to extend the GRASS program
search paths to include locally installed (see g.extension for details)
GRASS Addon modules which are not distributed with the standard GRASS
release.
GRASS_ADDON_BASE=/usr/grass-addons
In this example above path would be added to the standard GRASS path
environment.
If not defined by user, this variable is set by GRASS startup program
to $HOME/.grass7/addons on GNU/Linux and $APPDATA\GRASS7\addons on MS
Windows.
HTML Browser Variable
The GRASS_HTML_BROWSER environment variable allows the user to set the
HTML web browser to use for displaying help pages.
Running non-interactive batch jobs
If the GRASS_BATCH_JOB environment variable is set to the full path and
filename of a shell script then GRASS will be launched in a non-inter-
active way and the script will be run. The script itself can be inter-
active if that is what the user requires. When it is finished GRASS
will automatically exit using the exit-success code given by the
script. The script file must have its executable bit set.
EXAMPLES
The following are some examples of how you could start GRASS
grass78
Start GRASS using the default user interface. The user will be
prompted to choose the appropriate location and mapset.
grass78 --gui
Start GRASS using the graphical user interface. The user will be
prompted to choose the appropriate location and mapset.
grass78 --text
Start GRASS using the text-based user interface. Appropriate loca-
tion and mapset must be set by environmental variables (see exam-
ples below) otherwise taken from the last GRASS session.
grass78 --gtext
Start GRASS using the text-based user interface. The user will be
prompted to choose the appropriate location and mapset.
grass78 $HOME/grassdata/spearfish70/user1
Start GRASS using the default user interface and automatically
launch into the given mapset, bypassing the mapset selection menu.
grass78 --gui -
Start GRASS using the graphical user interface and try to obtain
the location and mapset from environment variables.
grass78 -c EPSG:4326 $HOME/grassdata/mylocation
Creates a new GRASS location with EPSG code 4326 (latitude-longi-
tude, WGS84) in the specified GISDBASE
grass78 -c EPSG:5514:3 $HOME/grassdata/mylocation
Creates a new GRASS location with EPSG code 5514 (S-JTSK / Krovak
East North - SJTSK) with datum transformation parameters used in
Czech Republic in the specified GISDBASE
grass78 -c XY $HOME/grassdata/gnomonic --exec g.proj -c
proj4=’+proj=gnom +lat_0=90 +lon_0=-50’
Creates a new GRASS location from PROJ definition string (here:
gnomonic) in the specified GISDBASE
grass78 -c myvector.shp $HOME/grassdata/mylocation
Creates a new GRASS location based on georeferenced Shapefile
grass78 -c myraster.tif $HOME/grassdata/mylocation
Creates a new GRASS location based on georeferenced GeoTIFF file
Batch jobs with the exec interface
Creating a new Location based on a geodata file’s projection (-c) and
exit (-e) immediately:
grass78 -c elevation.tiff -e /path/to/grassdata/test1/
Linking external raster data to PERMANENT Mapset:
grass78 /path/to/grassdata/test1/PERMANENT/ --exec r.external input=basins.tiff output=basins
grass78 /path/to/grassdata/test1/PERMANENT/ --exec r.external input=elevation.tiff output=elevation
Get statistics for one raster map:
grass78 /path/to/grassdata/test1/PERMANENT/ --exec r.univar map=elevation
Compare the rasters visually:
grass78 /path/to/grassdata/test1/PERMANENT/ --exec g.gui.mapswipe first=elevation second=basins
Execution of shell and Python scripts instead of single commands
A sequence of commands can be bundled in a script and executed using
the exec interface.
Shell script example: the command to execute a shell script might be:
grass78 /path/to/grassdata/test1/PERMANENT/ --exec sh test.sh
A very simple bash script ("test.sh") may look like this:
#!/bin/bash
g.region -p
g.list type=raster
r.info elevation
Python script example: the command to execute a Python script might be:
grass78 /path/to/grassdata/test1/PERMANENT/ --exec python test.py
A very simple Python script ("test.py") may look like this:
#!/usr/bin/env python3
# import GRASS Python bindings (see also pygrass)
import grass.script as gscript
import grass.script.setup as gsetup
gscript.message(’Current GRASS GIS 7 environment:’)
print(gscript.gisenv())
gscript.message(’Available raster maps:’)
for raster in gscript.list_strings(type=’raster’):
print(raster)
gscript.message(’Available vector maps:’)
for vector in gscript.list_strings(type=’vector’):
print(vector)
Using temporary location
Creating a new temporary location based on a georeferenced file’s pro-
jection coordinate reference system (CRS) and simultaneously starting
computation in a shell script:
grass78 --tmp-location elevation.tiff --exec test.sh
The same, but using an EPSG code and a Python script:
grass78 --tmp-location EPSG:3358 --exec test.py
Finally, for special cases, we can create an XY location without any
CRS:
grass78 --tmp-location XY --exec test.py
Temporary location is automatically deleted after computation, so the
script is expected to export, link or otherwise preserve the output
data before ending.
A single command can be also executed, e.g. to examine properties of
the temporary location:
grass78 --tmp-location EPSG:3358 --exec g.proj -p
A temporary XY location with single command is useful, e.g. to show
help text of a module:
grass78 --tmp-location XY --exec r.neighbors --help
Troubleshooting
Importantly, to avoid an "[Errno 8] Exec format error" there must be a
shebang line at the top of the script (like #!/bin/sh, #!/bin/bash, or
#!/usr/bin/env python3) indicating which interpreter to be used for the
script. The script file must have its executable bit set.
CAVEAT
If you start GRASS using the wxGUI interface you must have a python
command in your $PATH variable. That is, the command must be named
python and not something like python3.6. Rarely some Python installa-
tions do not create a python command. In these cases you can override
python by GRASS_PYTHON environmental variable.
Furthermore, if you have more than one version of Python installed,
make sure that the version you want to use with GRASS is set by
GRASS_PYTHON environmental variable.
SEE ALSO
List of GRASS environment variables
GRASS GIS Web site
GRASS GIS User Wiki
GRASS GIS Bug Tracker
GRASS GIS 7 Programmer’s Manual
AUTHORS (of this page)
Justin Hickey
Markus Neteler
Hamish Bowman
Martin Landa, Czech Technical University in Prague, Czech Republic
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GRASS 7.8.7 grass7(1)
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