Maciej Sieczka wrote: > Hi > > I've noticed that r.out.gdal creates GeoTIFFs significantly larger than > gdal_translate. Could this be avoided? Not completely, but file sizes are near identical (see below) in this version: http://markus.metz.giswork.googlepages.com/r.out.gdal.conservative.tar.gz The fix is to first create a new GDAL raster in memory and then copy the raster to the desired output format, after GDAL API Tutorial http://www.gdal.org/gdal_tutorial.html I guess, when GDAL creates a new raster instead of copying a raster, it reserves a bit of extra space just in case. Maybe this is analogous to gdalwarp as explained in [1,2]. > > Example, in spearfish60: > > $ r.out.gdal in=landcover.30m out=landcover.30m.tif type=Byte > $ ls -l landcover.30m.tif > -rw-r--r-- 1 shoofi shoofi 303978 sie 20 11:49 landcover.30m.tif > > $ gdal_translate landcover.30m.tif landcover.30m_gt.tif > $ ls -l landcover.30m_gt.tif > -rw-r--r-- 1 shoofi shoofi 300220 sie 20 11:49 landcover.30m_gt.tif > Now nearly the same size: Same commands give sizes 298928 for r.out.gdal and 298914 for gdal_translate. I did not export the colortable, thus the smaller file sizes on my system. > > Applying compression makes the difference more distinct: > > $ r.out.gdal in=landcover.30m out=landcover.30m.tif type=Byte > createopt="COMPRESS=DEFLATE" > $ ls -l landcover.30m.tif > -rw-r--r-- 1 shoofi shoofi 51338 sie 20 11:50 landcover.30m.tif > > $ gdal_translate -co "COMPRESS=DEFLATE" landcover.30m.tif > landcover.30m_gt.tif > $ ls -l landcover.30m_gt.tif > -rw-r--r-- 1 shoofi shoofi 47567 sie 20 11:51 landcover.30m_gt.tif Same commands give sizes 46275 for r.out.gdal and 46261 for gdal_translate. I did not export the colortable, thus the smaller file sizes on my system.
The size difference is in both cases now 14 bytes instead of about 3000 bytes. > > (Probably related to [1]. Some more info in a duplicate [2].) > > [1]http://trac.osgeo.org/gdal/ticket/1688 > [2]http://trac.osgeo.org/gdal/ticket/1689). > > Maciek > Markus _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
