grass7(1)

🌸 grass7(1) — GRASS GIS User's Manual 🌸

💖 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 welcome screen)
• --gtext — Indicates that Text-based User Interface should be used (show welcome screen)
• --gui — Indicates that Graphical User Interface (wxGUI) should be used
• --config — Prints GRASS configuration parameters (options: arch, build, compiler, date, path, revision, svn_revision, version)
• --exec EXECUTABLE — Execute GRASS module or script. The provided executable will be executed 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 PERMANENT 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 🦋

Okay so this command is literally the launch button for GRASS GIS. It parses the command line arguments and then initializes GRASS for the user. Since GRASS modules require a specific environment, this program must be called before any other GRASS module can run. The command line arguments are optional and give the user a method to indicate the desired user interface, 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 (without any options) will start GRASS with the previous settings for the user interface and mapset selected. It’s giving muscle memory, no cap. 🧠✨

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. Lowkey dramatic, but very helpful. 😭

💅 FLAGS 💅

The flag --config option prints GRASS GIS configuration and version parameters, 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 examples throughout the user manual pages are based upon it. Obsessed, honestly. 🍓

🎀 ENVIRONMENT VARIABLES 🎀

A number of environment variables are available at GRASS startup to assist with automation and customization. Most users will not need to bother with these. Bestie, you can skip this unless you’re doing the most. 💅

In addition to these shell environment variables GRASS maintains a number 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 environment 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). Periodt. 💖

💜 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 precedence 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 install 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 binaries 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-interactive way and the script will be run. The script itself can be interactive 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 ✨

okay so here's the part you actually came for 💅 these are all the ways you can start GRASS, and bestie there are so many:

• grass78 — starts GRASS with the default user interface. It's gonna ask you which location and mapset you want, so you pick.
• grass78 --gui — starts GRASS with the graphical user interface. Still gonna prompt you for the location and mapset.
• grass78 --text — starts GRASS with the text-based user interface. The location and mapset have to be set by environmental variables (there are examples below, don't panic) — otherwise it just grabs whatever you used in your last GRASS session.
• grass78 --gtext — text-based UI again, but this time it asks you to choose the appropriate location and mapset instead of pulling from last time.
• grass78 $HOME/grassdata/spearfish70/user1 — default UI, but it drops you straight into the mapset you named, no mapset selection menu, no waiting, we go straight in 🔥
• grass78 --gui - — graphical UI, and it tries to pull the location and mapset out of your environment variables.
• grass78 -c EPSG:4326 $HOME/grassdata/mylocation — creates a brand new GRASS location with EPSG code 4326 (that's latitude-longitude, WGS84) inside the GISDBASE you specified.
• grass78 -c EPSG:5514:3 $HOME/grassdata/mylocation — creates a new GRASS location with EPSG code 5514 (S-JTSK / Krovak East North - SJTSK), using the datum transformation parameters used in Czech Republic, inside 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 a PROJ definition string (here it's gnomonic, if you were wondering) inside the specified GISDBASE.
• grass78 -c myvector.shp $HOME/grassdata/mylocation — creates a new GRASS location based on a georeferenced Shapefile.
• grass78 -c myraster.tif $HOME/grassdata/mylocation — creates a new GRASS location based on a georeferenced GeoTIFF file.

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🍓 Batch jobs with the exec interface

Creating a new Location based on a geodata file's projection (-c) and then exiting (-e) immediately, no notes:

grass78 -c elevation.tiff -e /path/to/grassdata/test1/

Linking external raster data to the 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

Getting statistics for one raster map:

grass78 /path/to/grassdata/test1/PERMANENT/ --exec r.univar map=elevation

Comparing the rasters visually, because sometimes you just gotta look at it 👀:

grass78 /path/to/grassdata/test1/PERMANENT/ --exec g.gui.mapswipe first=elevation second=basins

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🧚 Execution of shell and Python scripts instead of single commands

You can bundle a whole sequence of commands into a script and run the whole thing through the exec interface. Obsessed honestly.

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)

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🌈 Using temporary location

Creating a new temporary location based on a georeferenced file's projection coordinate reference system (CRS) and simultaneously starting computation in a shell script:

grass78 --tmp-location elevation.tiff --exec test.sh

The same thing, but with an EPSG code and a Python script:

grass78 --tmp-location EPSG:3358 --exec test.py

And finally, for the special cases, you can create an XY location with no CRS at all:

grass78 --tmp-location XY --exec test.py

heads up bestie: the temporary location gets automatically deleted after computation. so your script is expected to export, link, or otherwise preserve the output data before it ends. do not forget this, i'm begging 😭

A single command can also be executed, e.g. to examine properties of the temporary location:

grass78 --tmp-location EPSG:3358 --exec g.proj -p

A temporary XY location with a single command is useful, e.g. to show the help text of a module:

grass78 --tmp-location XY --exec r.neighbors --help

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💀 Troubleshooting

Importantly — and this is the one that gets everybody — 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 is supposed to be used for the script. And the script file must have its executable bit set. that's it, that's the whole fix 🫶

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😭 CAVEAT

If you start GRASS using the wxGUI interface, you must have a python command in your $PATH variable. Like, the command has to literally be named python and not something like python3.6. Sometimes (rarely!) some Python installations just don't create a python command at all. In those cases you can override python with the GRASS_PYTHON environmental variable. slay, there's a way out.

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 the GRASS_PYTHON environmental variable. don't let them fight it out in there 💅

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👑 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

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🌸 AUTHORS (of this page)

• Justin Hickey
• Markus Neteler
• Hamish Bowman
• Martin Landa, Czech Technical University in Prague, Czech Republic

Main index | Topics index | Keywords index | Graphical index | Full index

© 2003-2022 GRASS Development Team, GRASS GIS 7.8.7 Reference Manual

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and that's the whole page bestie 🎀 this is straight out of the GRASS GIS 7.8.7 Reference Manual, © 2003-2022 GRASS Development Team, and the footer down at the bottom literally just says GRASS 7.8.7 over on the left with grass7(1) on the right. iconic. go touch some grass. literally. it's a GIS thing 💖✨