you can surely identify the valid pixels with visualization software such as qgis, using the valuetool plugin, to identify the 4 corners of the valid region.
Another option is to compress the gtiff with e.g. DEFLATE compression like this gdal_translate -co COMPRESS=DEFLATE in.tif out.tif Etienne On Thu, Oct 25, 2012 at 1:32 PM, katrin eggert <katrineggert1...@gmail.com> wrote: > Hello > No I don't know where my valid pixels are. > Any alternative? > > 2012/10/25 Kyle Shannon <k...@pobox.com> >> >> Katrin, >> Do you know where you valid pixels are in the image? If so, >> gdal_translate with -srcwin would work: >> >> kyle@ubuntu:~$ gdal_translate -srcwin xoff yoff 60 100 in.tif out.tif >> >> where xoff, yoff are the number of pixels from the image origin that your >> valid region begins(pixels, lines). See http://gdal.org/gdal_translate.html >> for more info. >> >> >> >> On Thu, Oct 25, 2012 at 8:05 AM, katrin eggert >> <katrineggert1...@gmail.com> wrote: >>> >>> Greetings >>> I have a Geotif with only one Layer with a size of 6000x5000 but from >>> which I only have a square of 60x100 with bvalid pixels. the remaining are >>> NOdata. The problem is that this Geotiff is a big file 90MB and without >>> these NoData values I would have a much smaller raster. >>> How can I generate a new Geotiff without these noValid values and with >>> extent adjusted to the valid pixels? >>> Thank you >>> Regards, >>> Katrin E. >>> >>> _______________________________________________ >>> gdal-dev mailing list >>> gdal-dev@lists.osgeo.org >>> http://lists.osgeo.org/mailman/listinfo/gdal-dev >> >> > > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
