readRAST6() in {spgrass6}

It is hard to know what the upper-limit is on Windows-- as the memory
is usually fragmented by the operating system.

Since you are using GRASS, I would first try a coarsened version of
your terrain-shape rasters via the built-in re-sampling functionality.
While this is not ideal, as it is NN-based, it will give a quick way
to try out methods.

After you have initialized your GRASS connection in R, execute something like:

system('g.region res=10 -ap')

This will align the region along a 10x10 map unit grid. All further
interaction with raster data will be automatically re-sampled to this
grid system.

Dylan

On Mon, May 16, 2011 at 2:25 PM, Sam Prentice <sep at umail.ucsb.edu> wrote:

Thanks you for your suggestions. This error is not affected by choice of
mapset, and is not limited by my hardware.

Further info: I'm running 64-bit windows, 16MB memory, w/multiple cores.
GRASS 6.4.1, R 2.12.2. I'm running standalone R using initGRASS() to set
GRASS env parameters. The GRASS files I'm trying to read-in are DEM
derivatives, each ~170MB. The intermediate .tmp file in the error message is
300MB.

It's been suggested that I am "likely trying to import too much data into
R". Assuming non-limiting computer power, what is the upper bound on amount
of data that can be read into R from GRASS? If not a fixed amount, what are
the main conditions that cause it to vary? I did not see this addressed in
the {spgrass6} documentation, so I'm assuming it's a base R limitation, but
maybe not? Quantifying this limitation will help determined how to move
forward (e.g, resampling at smaller scale versus subsetting my DEM
derivatives).

Thanks,
Sam

|-----Original Message-----
|From: Pierre Roudier [mailto:pierre.roudier at gmail.com]
|Sent: Tuesday, May 10, 2011 3:40 PM
|To: Sam Prentice
|Cc: r-sig-geo at r-project.org
|Subject: Re: [R-sig-Geo] readRAST6() in {spgrass6}
|
|Could that message have anything to do with the fact that this is a layer
from
|the PERMANENT mapset?
|
|My two cents,
|
|Pierre
|
|2011/5/11 Sam Prentice <sep at umail.ucsb.edu>:
|> Hi,
|>
|>
|>
|> I'm running R 2.12.2 via Tinn-R on Windows Server 2008. I'm using R
|> for cluster analysis for terrain classification and I'm getting the
|> following error when parsing GRASS data into R:
|>
|>
|>
|>> x =
|>
|readRAST6(c("param_elev3","param_crosC_1m","param_longC_1m","param
|_slope5","
|> param_profC","param_miniC_1m","param_maxiC_1m"))
|>
|> D:/GRASSdata/Sedgwick2/PERMANENT/.tmp/param_elev3 has GDAL driver
|> GTiff
|>
|> and has 6224 rows and 6242 columns
|>
|>
|>
|> Error in deleteDataset(DS) :
|>
|> ? ? ? ? ? ? ? ?GDAL Error 1: Deleting
|> D:/GRASSdata/Sedgwick2/PERMANENT/.tmp/param_elev3 failed:
|>
|> Permission denied
|>
|>
|>
|> On the surface this looked like an issue with user privileges, since I
|> do not have admin-level user privileges on this machine. However, this
|> has been corrected - I now have permissions on the .tmp directory
|> listed in the error, and I can create, append, and delete any file in
|> that location, but the error is still occurring.
|>
|>
|>
|> Thoughts?
|>
|>
|>
|> Thanks,
|>
|> Sam
|>
|>
|> ? ? ? ?[[alternative HTML version deleted]]
|>
|> _______________________________________________
|> R-sig-Geo mailing list
|> R-sig-Geo at r-project.org
|> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
|>
|
|
|
|--
|Scientist
|Landcare Research, New Zealand