[R-sig-Geo] readRAST6() in {spgrass6}

[Dylan Beaudette]

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]]
> |>
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> |
> |
> |
> |--
> |Scientist
> |Landcare Research, New Zealand
>
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