[GRASSLIST:2739] Re: compiling grass and gd includes

Glynn Clements glynn.clements at virgin.net
Wed Dec 5 14:43:45 EST 2001

cmbarton wrote:

> Thanks very much for the help. I will do this if needed. However, I have 
> the PNG library, but don't know what it does for GRASS.

The PNG library is necessary for r.in.png, r.out.png, and the PNG

> What does GD do 

GD provides a typical set of drawing commands (lines, polygons,
rasters, text) which draw into a PNG image.

> and what do I lose if I disable it?

The PNG driver; this allows you to do "d.mon start=PNG", to create PNG
images using GRASS display commands.

> Also, I do have GDAL installed, but GRASS doesn't want to build to it. I 
> have included the --with-libs and  --with-includes  switchs to point to 
> my lib and include directories. I have been using GDAL in the 
> precompiled binary (for MacOSX) and want to continue to do so.

By default, r.in.gdal isn't linked against libgdal. It loads libgdal
at run time using dlopen(). I don't know whether this works on MacOSX.

You can force libgdal to be linked at compile time using configure's
"--with-gdal" switch. If an argument is specified, it is the path to
the "gdal-config" script. Otherwise gdal-config needs to be in your
path (configure uses gdal-config to obtain the necessary compiler and
linker switches).

Glynn Clements <glynn.clements at virgin.net>

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