rgdal package installation
If you use OS X with the Homebrew package manager, and have R installed through the homebrew-science tap, you can install rgdal by first installing gdal.
brew install gdal
You may first want to list the options available before you run this in case you want something fancy like postgresql support. To see the available options type
brew options gdal
then to be fancy you can type
brew install --with-postgresql gdal
after a while you should be good to go with dependencies, since proj including your needed proj_api.h are dependencies! Unfortunately, rgdal still won't find pro_api.h right now since it isn't looking in /usr/local/include. To fix this and other possible maladies with your rgdal installation, use the following R command to install rgdal:
> install.packages('rgdal', type = "source", configure.args=c('--with-proj-include=/usr/local/include','--with-proj-lib=/usr/local/lib'))
This should be similar to what you would also need for MacPorts with the exception of the brew steps, and your libraries/headers are most likely under "/opt/local/lib" and "/opt/local/include" respectively.
Note: to brew upgraders if you are using "--with-armadillo" as an option with gdal, and upgraded armadillo to 7 from 6. You will have to recompile gdal before you upgrade/reinstall rgdal.
I f you look at the package page on CRAN, you will see the following :
SystemRequirements: for building from source: GDAL >= 1.7.1 library from http://trac.osgeo.org/gdal/wiki/DownloadSource and PROJ.4 (proj >= 4.4.9) from http://trac.osgeo.org/proj/; GDAL OSX frameworks built by William Kyngesburye at http://www.kyngchaos.com/ may be used for source installs on OSX.
As you seem to be under Linux, you always build package from source, so you will have to install the corresponding libraries on your system. If you are under Mint, Ubuntu or another Debian derivative, you can do :
$ sudo apt-get install libgdal1-dev libproj-dev
One tip that can be useful, still under a Debian based system, is to install the apt-file
package and run :
$ sudo apt-file update
Then, when you get an error such as :
configure: error: proj_api.h not found in standard or given locations.
You can use the following command to find which package you must install to get the missing file :
$ apt-file search proj_api.h
libproj-dev: /usr/include/proj_api.h