% GOPROJ : A go wrapper for PROJ the coordinate transformation software
% Didier Richard
% 2019/03/10

---

Revision:

* 2019/03/10 : first draft
* 2019/05/01 : second release

---

Rational

To provide a wrapper in Golang for PROJ and learn cgo mechanism 😃

Compiling PROJ 6.x.y

Download source file via proj-6.x.y.tar.gz. Download datum grids via proj-datumgrid-n.m.zip.

$ cd $GOPATH/src/osgeo.org/proj/usr/local/src
$ tar xzf PATH_TO/proj-6.x.y.tar.gz
$ cd proj-6.x.y/data
$ unzip PATH_TO/proj-datumgrid-n.m.zip

In the $GOPATH/src/osgeo.org/proj/usr/local/src/proj-6.x.y directory :

export PROJ_LIB=$GOPATH/src/osgeo.org/proj/usr/local/share/proj
./configure --prefix=$GOPATH/src/osgeo.org/proj/usr/local --disable-static
make -j$(nproc)
make install
make check
make clean
unset PROJ_LIB

Il faut aussi passer dans les dossiers $GOPATH/src/osgeo.org/proj/usr/local/{bin,include,lib} et retirer les fichiers "anciens" (dont la date est antérieure à l'installation).

Building the project

• To generate the Gopkg.lock file (first time) :

make dep-install

• To test the wrapper :

make test

• To install the wrapper :

make install

Miscellaneous

If the PROJ library and the PROJ files are not installed in usual places (like /usr/lib or /usr/lib/x86_64-linux-gnu/ for the former and /usr/share/proj for the latter), don't forget upon wrapper's installation to have the LD_LIBRARY_PATH set to point at the PROJ library and PROJ_LIB to the directory where proj.db is.

Whilst Makefile is ready to work on other operating systems (like windows and darwin), one has to compile the PROJ on those systems 😉