[R-sig-Geo] "Accessing" command line gdal?

[Roger Bivand]

On Sun, 6 Jan 2013, Jonathan Greenberg wrote:

> r-sig-geo'ers: is there a way to use rgdal to look for where the gdal
> installation is hiding?  In other words: if I wanted to write a modified
> wrapper for some gdal function (e.g. gdal_translate), how do I locate gdal
> assuming rgdal has been installed?  I am correct in assuming rgdal installs
> GDAL, correct?

Please never assume, just check? If you are thinking of a source install, 
of course nothing is installed, as GDAL etc. are external dependencies. If 
you mean the Windows or OSX binary rgdal packages from CRAN, check by 
looking inside the compressed archive files on CRAN (answer, given many 
times here, no, they are built static, so rgdal.dll and rgdal.dylib 
contain all the GDAL etc. binary objects needed to run, nothing more). 
rgdal does not install any GDAL utility programs etc. for obvious reasons.

rgdal cannot know about the GDAL install, but system("gdal-config") may 
tell you something on systems with GDAL installed externally. On 
Windows/OSX with rgdal installed as a CRAN binary, this will probably mean 
that the GDAL used in rgdal and the external GDAL may differ in version, 
and this should be checked by the user if it matters.

Hope this clarifies,

Roger

>
> --j
>
>

-- 
Roger Bivand
Department of Economics, NHH Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no