Markus Metz pisze:
Maciej Sieczka wrote:
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
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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
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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].
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.
Cool! The size difference due to colortable is a non-issue. I can't invest time in testing Markus's modifications thorougly, but this particular improvement would be great to have.
(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 -- Maciej Sieczka www.sieczka.org _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
