AW: [GRASS-user] Export of GeoTIFF

[Christian Braun]

Hi,

I did it with the batch convert. First do r.out.arc and then provide
gdal_trnaslate with options a_srs "EPSG:2169", a_nodata -9999 and
interleave=pixel

Thanks for your fast reply,
Christian

> -----Ursprüngliche Nachricht-----
> Von: Maciej Sieczka [mailto:tutey at o2.pl]
> Gesendet: Mittwoch, 10. Oktober 2007 09:52
> An: christian.braun at tudor.lu
> Cc: grassuser at grass.itc.it
> Betreff: Re: [GRASS-user] Export of GeoTIFF
> 
> christian.braun at tudor.lu wrote:
> 
> > I have serious problems exporting GRASS DCELL rasters to GeoTIFF.
> > I used r.out.gdal with type=Float32 and set the compression to LZW.
> > What I got later on in ArcView 3.3 is pure noise fort he picture and
> in
> > ArcGIS 9.2 I get some strange results.
> > The NULL values of the picture get a cryptic code like -1#QUAN1 and
> if
> > there are pixels with value 0 they become NoData in ArcGIS.
> 
> Christian,
> 
> Do the GeoTIFFs look OK in other software e.g. QGIS or OpenEV?
> 
> What GRASS version? r.out.gdal in GRASS < 6.3 is a shell
> script (wrapper around gdal_translate) and works well
> AFAICT. It's also present in GRASS 6.3 as r.out.gdal.sh.
> 
> But, the r.out.gdal in 6.3 is a new module written in C, and
>  it has a bug about null data handling [1]. I'm not sure,
> but maybe it's related.
> 
> Please try the shell script r.out.gdal version and let us
> know if it works.
> 
> If neither does please provide a sample dataset and a
> procedure to reproduce the error.
> 
> > I need to have them as GeoTIFFs for the easy im- and export. I am
> aware
> > that I can also use r.out.ascii but then I have to do an import
> procedure
> > in ArcGIS. For nearly 1000 images that is a bit hard to do.
> 
> As a workaround you can export with r.out.ascii and
> batch-convert them into GeoTIFF with gdal_translate, eg.
> given that your ascii rasters have "asc" extension:
> 
> for i in *.asc; do gdal_translate (your options go here) $i
> $i.tif; done
> 
> [1]http://wald.intevation.org/tracker/?func=detail&aid=405&group_id=21&
> atid=204
> 
> Maciek