Install GRASS from source code

August 4, 2025 ยท View on GitHub

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Table of contents

  • PREREQUISITES
  • (A) SOURCE CODE DISTRIBUTION
  • (B) COMPILATION
  • (C) COMPILATION NOTES for 64bit platforms
  • (D) INSTALLATION (first time)
  • (E) INSTALLATION ON MACOSX
  • (F) RUNNING GRASS
  • (G) UPDATE OF SOURCE CODE
  • (H) COMPILING INDIVIDUAL MODULES - OWN MODULES
  • (I) CODE OPTIMIZATION
  • (J) DEBUGGING OPTIONS
  • (K) SUPPORT
  • (L) GRASS PROGRAMMER'S MANUAL
  • (M) CONTRIBUTING CODE AND PATCHES

PREREQUISITES

The install order matters. GRASS needs at least two libraries which have to be installed before installing/compiling GRASS: For links to the software, see REQUIREMENTS.md in this directory.

Installation order:

  1. PROJ
  2. GDAL/OGR (compiled without GRASS support)
  3. optionally: databases such as PostgreSQL, MySQL, SQLite
  4. GRASS
  5. optionally: GDAL-OGR-GRASS plugin

(A) SOURCE CODE DISTRIBUTION

GRASS source code is currently distributed in 2 forms:

Officially released source code

The full source code version contains all the GRASS source code required for compilation. It is distributed as one file (*.tar.gz package) and the version is composed of 3 numbers, e.g. 3.7.0, 3.7.1 etc. See https://github.com/OSGeo/grass/releases.

Snapshots of source code (generated from GitHub)

This version of the source code can be acquired either from the GitHub repository (https://github.com/OSGeo/grass/) or as a auto-generated snapshot (*.tar.gz package) of the GitHub repository. The snapshot name contains the date when the snapshot was created (checked out from the GitHub repository), e.g. grass-3.7.git_src_snapshot_2022_04_27.tar.gz from https://grass.osgeo.org/grass-devel/source/snapshot/

(B) COMPILATION

IMPORTANT: All Unix based distributions are different. For Solaris, see hints below.

The command,

./configure --help

explains the options used to disable the compilation of non-mandatory GRASS modules. See REQUIREMENTS.md for details on dependencies. Detailed Wiki notes for various operating systems (MS-Windows, GNU/Linux distributions, FreeBSD, AIX, etc) are available at: https://grasswiki.osgeo.org/wiki/Compile_and_Install

First step of the compilation (-g for debugging, or -O2 for optimization):

CFLAGS="-g -Wall" ./configure

Explanation of make targets:

make install       - installs the binary

make bindist       - make a binary package with install script

make srcdist       - make a source package for distribution
make srclibsdist   - make a source package for library distribution

make libs          - make libraries only

make clean         - delete all files created by 'make'
make distclean     - 'make clean' + delete all files created by './configure'
make libsclean     - clean libraries compiled by 'make libs'

make htmldocs      - generate programmer's documentation as HTML files
make packagehtmldocs - package programmer's documentation in HTML
make pdfdocs       - generate programmer's documentation as PDF files

Next step is the compilation itself:

make

Note for Solaris users (see also Wiki page above):

To configure GRASS correctly on a system which doesn't have a suitable install program (AC_PROG_INSTALL ignores versions which are known to have problems), you need to ensure that $srcdir is an absolute path, by using e.g.:

`pwd`/configure ...

or:

./configure --srcdir=`pwd` ...

Then proceed as described above.

Note when using a compiler different from "gcc":

By setting environment variables, the compiler names can be defined (C and C++):

CC=cc CPP=cpp ./configure ...

(C) COMPILATION NOTES for 64bit platforms

To successfully compile GRASS on 64bit platforms, the required FFTW library has to be compiled with -fPIC flag:

#this applies to FFTW3, not to GRASS:
cd fftw-3.3.4/
CFLAGS="-fPIC" ./configure
make
make install

(D) INSTALLATION (first time)

After compilation, the resulting code is stored in the directory

./dist.$ARCH/

and the script (grass) in

./bin.$ARCH/

To run GRASS, simply start

./bin.$ARCH/grass

or run

make install
grass

(E) INSTALLATION ON MACOSX

See the ReadMe.rtf in the ./macosx/ folder and the Wiki page above.

(F) RUNNING GRASS

Download a sample data package from the GRASS web site, see https://grass.osgeo.org/download/sample-data/

Extract the data set and point the "Database" field in the GRASS startup menu to the extracted directory.

Enjoy.

(G) UPDATE OF SOURCE CODE

Assuming that you want to update your current installation from GitHub, you have to perform a few steps. In general:

  • update from GitHub
  • configure, compile

In detail:

cd /where/your/grass-source-code/lives/
git fetch --all
git merge upstream/main
./configure ...
make
make install

For details, see Guide to contributing on GitHub.

(H) COMPILING INDIVIDUAL MODULES - OWN MODULES

To compile (self-made) GRASS modules or to compile modified modules at least the GRASS libraries have to be compiled locally. This is done by launching:

make libs

Then change into the module's directory and launch the "make" command. The installation can be either done with "make install" from the main source code directory or locally with

"INST_NOW=y make"

You may want to define an alias for this:

alias gmake='INST_NOW=y make'

Then simply compile/install the current module with

gmake

Note: If you keep your module source code outside the standard GRASS source code directory structure, you will have to change the relative path(s) in the Makefile to absolute path(s).

(I) CODE OPTIMIZATION

If you would like to set compiler optimisations, for a possibly faster binary, type (don't enter a ";" anywhere):

CFLAGS=-O ./configure

or,

setenv CFLAGS -O
./configure

whichever works on your shell. Use -O2 instead of -O if your compiler supports this (note: O is the letter, not zero). Using the "gcc" compiler, you can also specify processor specific flags (examples, please suggest better settings to us):

CFLAGS="-mcpu=athlon -O2" # AMD Athlon processor with code optimisations
CFLAGS="-mcpu=pentium" # Intel Pentium processor
CFLAGS="-mcpu=pentium4" # Intel Pentium4 processor
CFLAGS="-O2 -msse -msse2 -mfpmath=sse \
        -minline-all-stringops" # Intel XEON 64bit processor
CFLAGS="-mtune=nocona -m64 -minline-all-stringops" # Intel Pentium 64bit processor

Note: As of version 4.3.0, GCC offers the -march=native switch that enables CPU auto-detection and automatically selects optimizations supported by the local machine at GCC runtime including -mtune.

To find out optional CFLAGS for your platform, enter:

gcc -dumpspecs

See also: https://gcc.gnu.org/

A real fast GRASS version (and small binaries) will be created with LDFLAGS set to "stripping" (but this disables debugging):

CFLAGS="-O2 -mcpu=<cpu_see_above> -Wall" LDFLAGS="-s" ./configure

(J) DEBUGGING OPTIONS

The LDFLAGS="" part must be undefined as -s will strip the debugging information.

Don't use -O for CFLAGS if you want to be able to step through function bodies. When optimisation is enabled, the compiler will re-order statements and re-arrange expressions, resulting in object code which barely resembles the source code.

The -g and -Wall compiler flags are often useful for assisting debugging:

CFLAGS="-g -Wall" ./configure

See also the file ./doc/debugging.txt and the Wiki page https://grasswiki.osgeo.org/wiki/GRASS_Debugging

(K) SUPPORT

Note that this code is still actively being developed and errors inevitably turn up. If you find a bug, please report it to the GRASS bug tracking system so we can fix it. See https://grass.osgeo.org/contribute/

If you are interested in helping to develop GRASS, please join the GRASS developers mailing list. See https://grass.osgeo.org/development/

(L) GRASS PROGRAMMER'S MANUAL

The Programmer's manual https://grass.osgeo.org/programming8/ is generated from the source code. This requires the installation of doxygen (http://www.doxygen.nl) and optionally Graphviz dot (https://graphviz.org/doc/info/command.html).

The main file is: ./grasslib.dox where all sub-documents have to be linked to.

To locally generate the 'Programmer's Manual', run

make htmldocs

To generate documentation as a single html file (recommended for simple reading)

make htmldocs-single

This process takes some time. The result will be found in the file lib/html/index.html.

To generate the 'Programmer's Manual' in PDF format, run

make pdfdocs

(M) CONTRIBUTING CODE AND PATCHES

Please see

Authors

Markus Neteler and the GRASS Development Team