proj  6.1.0
About: PROJ.4 is a cartographic projections library.
  Fossies Dox: proj-6.1.0.tar.gz  ("inofficial" and yet experimental doxygen-generated source code documentation)  

proj Documentation

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PROJ is a generic coordinate transformation software, that transforms coordinates from one coordinate reference system (CRS) to another. This includes cartographic projections as well as geodetic transformations.

For more information on the PROJ.4 project please see the web page at:

The PROJ.4 mailing list can be found at:

See the NEWS file for changes between versions.

The following command line utilities are included in the PROJ package:

  • proj, for cartographic projection of geodetic coordinates
  • cs2cs, for transformation from one CRS to another CRS.
  • geod, for geodesic (great circle) computations.
  • cct, for generic Coordinate Conversions and Transformations.
  • gie, the Geospatial Integrity Investigation Environment.
  • projinfo, for geodetic object and coordinate operation queries


Build dependencies

PROJ requires C and C++11 compilers. It also requires SQLite3 (headers, library and executable).

Building with CMake

cd proj
mkdir build
cd build
cmake ..
cmake --build .

On Windows, one may need to specify generator:

cmake -G "Visual Studio 15 2017" ..

If the SQLite3 dependency is installed in a custom location, specify the paths to the include directory and the library:

cmake -DSQLITE3_INCLUDE_DIR=/opt/SQLite/include -DSQLITE3_LIBRARY=/opt/SQLite/lib/ ..

Tests are run with


The test suite requires that the proj-datumgrid package is installed in PROJ_LIB.

Building on Unix/Linux

FSF's configuration procedure is used to ease installation of the PROJ system.

The default destination path prefix for installed files is /usr/local. Results from the installation script will be placed into subdirectories bin, include, lib, man/man1 and man/man3. If this default path prefix is proper, then execute:


See the note below if you are building PROJ directly from the git repository.

If another path prefix is required, then execute:

./configure --prefix=/my/path

In either case, the directory of the prefix path must exist and be writable by the installer. After executing configure, execute:

make install

The install target will create, if necessary, all required sub-directories.

Tests are run with

make check

The test suite requires that the proj-datumgrid package is installed in PROJ_LIB.

Building from the git repository

If you are building from the git repository you have to first run


which will generate a configure script that can be used as described above.

Distribution files and format

Sources are distributed in one or more files. The principle elements of the system are in a compress tar file named proj-x.y.z.tar.gz where "x" will indicate major release number, "y" indicates minor release number and "z" indicates the patch number of the release.

In addition to the PROJ software package, distributions of datum conversion grid files and PROJ parameter files are also available. The grid package is distributed under the name, where "x" is the major release version and "y" the minor release version numbers. Similarly regional packages are distributed. The regional packages contain resources that are not essential to the functionality of PROJ but still of value to users in the region specific to the package. All grids that were in proj-datumgrids-1.6 remain in proj-datumgrids-1.7; the regional datumgrid files contain grids for datums not previously supported (prior to PROJ 5.0.0).

The resource packages can be downloaded from the PROJ.4 website.

More info on the contents of the various resource packages can be found at the proj-datumgrid GitHub repository.

The resource file packages should be extracted to PROJ_LIB where PROJ will find them after installation. The default location of PROJ_LIB on UNIX-based systems is /usr/local/share/proj but it may be changed to a different directory. On Windows you have to define PROJ_LIB yourself.

Citing PROJ in publications