You can use readGDAL and writeGDAL. If you really need lower level gdal
functions you can look at the code of these functions. you can also use
functions from 'raster':

library(raster)
r <- raster(fname)
x <- r * 2
x <- writeRaster( x, "t1.tif")
plot(x)


On Tue, Aug 28, 2012 at 5:27 AM, cpadwick <cpadwick@hotmail.com> wrote:

> Hi, I want to read an existing geotiff file (with georeferencing info),
> operate on the raster data, and write out the result to a Float32 file.
>  I'm
> working with hyperion data which is Integer.
>
> This code creates an outputfile, however, the output file t1.tif is
> Integer.
> I need it to be float.
>
> fname = "./EO1H0420362001131100P1/EO1H0420362001131100P1_B023_L1T.TIF"
> x <- GDAL.open(fname, read.only=TRUE)
> tmp = getRasterData(x)
> xx <- copyDataset(x, driver="GTiff")
> putRasterData(xx, tmp+1)
> saveDataset(xx, "t1.tif")
> GDAL.close(x)
> GDAL.close(xx)
>
> This code creates a Float32 file, however, the geo referencing information
> is lost:
>
> x <- GDAL.open(fname, read.only=TRUE)
> tmp = getRasterData(x)
> xx <- new("GDALTransientDataset", driver=new("GDALDriver", "GTiff"),
>   rows=ncol(tmp), cols=nrow(tmp), bands=1, type="Float32")
> putRasterData(xx, tmp+1)
> saveDataset(xx, "t2.tif")
> GDAL.close(x)
> GDAL.close(xx)
>
> This code fails with the following error:
>
> Error in function (classes, fdef, mtable)  :
>   unable to find an inherited method for function "gridded", for signature
> "GDALTransientDataset"
>
> x <- GDAL.open(fname, read.only=TRUE)
> tmp = getRasterData(x)
> xx <- copyDataset(x, driver="GTiff")
> putRasterData(xx, tmp+1)
> writeGDAL(xx, "t3.tif")
> GDAL.close(x)
> GDAL.close(xx)
>
> Any help will be greatly appreciated.
>
>
>
>
>
>
> --
> View this message in context:
> http://r-sig-geo.2731867.n2.nabble.com/problems-writing-a-tiff-file-with-georeferencing-tp7580850.html
> Sent from the R-sig-geo mailing list archive at Nabble.com.
>
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