[R-sig-Geo] GDAL problem writing Idrisi format

[Roger Bivand]

On Fri, 14 Aug 2009, Alberto Ruiz Moreno wrote:

> I get the error
>
> GDAL Error 4: `C:\DOCUME~1\Temp\Rtmplib5Gm\file5f906952' not recognised as a supported file format.
>
> When a try to write a SpatialGridDataframe as Idrisi A.1 raster format
>
>> x <- readGDAL(system.file("external/test.ag", package="sp")[1])
>
> C:/ARCHIV~1/R/R-29~1.1/library/sp/external/test.ag has GDAL driver AAIGrid
> and has 115 rows and 80 columns
>
>> writeGDAL(x,'test.tiff',drivername='GTiff')
>
> That?s OK but..
>
>> writeGDAL(x,'test.rst',drivername='RST')
> Error en .local(.Object, ...) :
>        GDAL Error 4: `C:\DOCUME~1\ARUIZ~1.EEZ\CONFIG~1\Temp\Rtmplib5Gm\file5f906952' not recognised as a supported file format.

This particular driver is written requiring that all files used must use 
the *.rst extension for the raw image file. writeGDAL() creates a file 
corresponding to the required GDAL dataset in the R temporary folder with 
a temporary name with no extension, so when the correctly constructed file 
is being opened, the attempt error exits, because the file extension is 
wrong.

I'll try to find a workaround in the next release of rgdal (after the one 
on its way to CRAN now). I'll try it on you first, if that's OK - 
apparently the driver also likes having environment variable IDRISIDIR set 
pointing to your installed Idrisi.

Roger


>
>> summary(x)
> Object of class SpatialGridDataFrame
> Coordinates:
>     min    max
> x 178400 181600
> y 329400 334000
> Is projected: NA
> proj4string : [NA]
> Number of points: 2
> Grid attributes:
>  cellcentre.offset cellsize cells.dim
> x            178420       40        80
> y            329420       40       115
> Data attributes:
>   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.    NA's
>  128.4   293.2   371.4   423.2   499.8  1806.0  6097.0
>
>> version
>               _
> platform       i386-pc-mingw32
> arch           i386
> os             mingw32
> system         i386, mingw32
> status
> major          2
> minor          9.1
> year           2009
> month          06
> day            26
> svn rev        48839
> language       R
> version.string R version 2.9.1 (2009-06-26)
>
> Thank for any comment...
>
>
>
>
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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, 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