rgdal and grass rasters

As far as sample code goes, simply getting
grass_to_raster=raster("somegrassfile") is my goal -- my understanding
is anything rgdal can read, raster can read.  Running your command I
do get:

GRASS (ro): GRASS Database Rasters (5.7+)

But with rgdal:

require(rgdal)
gdaldrivers=getGDALDriverNames()
gdaldrivers$create[gdaldrivers$name=="GRASS"]
[1] FALSE
gdaldrivers$copy[gdaldrivers$name=="GRASS"]
[1] FALSE
gdaldrivers$create[gdaldrivers$name=="GTiff"]
[1] TRUE
gdaldrivers$copy[gdaldrivers$name=="GTiff"]
[1] TRUE

Am I perhaps missing an rgdal installation flag that is required to
enable GRASS rasters?

--j

On Mon, Mar 1, 2010 at 6:04 PM, Dylan Beaudette
<dylan.beaudette at gmail.com> wrote:

Roger can likely point out the problem after some example code is
posted. In the mean time I would suggest checking to make sure your
GDAL is compiled _without_ GRASS support, and that the GDAL GRASS
plugin is correctly installed.

This is how I check on my machine:

gdal_translate --formats | grep -i grass
?GRASS (ro): GRASS Database Rasters (5.7+)

Cheers,
Dylan

On Mon, Mar 1, 2010 at 5:44 PM, Alex Mandel <tech_dev at wildintellect.com> wrote:

spgrass6 is a an R package and has read/write access to GRASS datasets.
It's usage would be instead of rgdal(well sorta, rgdal is required by
spgrass6). Both write objects to sp types.
You can use it from within R to start a GRASS session or within GRASS to
start a linked R session.
http://cran.r-project.org/web/packages/spgrass6/index.html

I got GDALinfo to work on my machine, I wonder if your just missing the
gdal-grass library, or libgrass.

On ubuntu it's something like libgdal1-1.6.0-grass
I know qgis needs this to work with GRASS not sure about gdal itself but
based on http://gdal.org/frmt_grass.html probably. Also note that page
talks about the path to a dataset that should be used.


Thanks,
Alex

Hmm, I'm trying to use the raster package via rgdal to access these
files -- I'm trying to avoid having to export then to another format
(I'm dealing with gigabytes of rasters), although I suppose I could do
this. ?Does spgrass6 "enable" rgdal to access GRASS rasters, or is it
its own standalone program? ?How does the base gdal package work with
grass rasters?

--j

On Mon, Mar 1, 2010 at 2:35 PM, Sarah Goslee <sarah.goslee at gmail.com> wrote:

I think you need to export it from grass first, with r.out.gdal

Or you can use spgrass6 to work with R and GRASS directly.

Sarah

On Mon, Mar 1, 2010 at 5:17 PM, Jonathan Greenberg
<greenberg at ucdavis.edu> wrote:

Folks: when trying to import or GDALinfo a grass raster, where,
exactly, should I be pointing to in the grass directory? ?I tried
pointing to the file with the same name as the raster I want to work
with in the fcell, cellhd, and cell directories
(grass/location/mapset), but none of these are working... ?thanks!

--
Sarah Goslee
http://www.functionaldiversity.org