Giovanni, You can use the -et option of gdalwarp. [1]
Are you sure qgis is warping the whole image and not just the scaled down version of the original? Processing a half giga pixel image ought to be longer than instantaneous. [1]: http://www.gdal.org/gdalwarp.html On Wed, Jun 1, 2011 at 9:55 PM, G. Allegri <[email protected]> wrote: > I was doing some tests on Gvsig for raster reprojection, where gdal warp is > used. Gvsig uses a default error threshold of 0.125, which AFAIK makes gdal > warp fall back to an approximate transformation. Anyway the reprojection is > quite slow, even if significantly faster then GDALGenImgProjTransform. > > My test is against a 21698P x 24647L ArcInfo Binary Grid, with a single > band with block dimensions 256x4. Bot SRSs are projected. > The command is: > gdalwarp -s_srs EPSG:3003 -t_srs EPSG:23032 -et 0.125 > hdr.adf test.tiff > It took about 9 minutes to complete. > > Loading the same raster on QGis, which implements its own approximate > transformation for on-the-fly reprojection [1], is istantaneous. > I was wondering if a similar algorithm could be use within Gdal... > > Giovanni > > [1] > http://trac.osgeo.org/qgis/browser/trunk/qgis/src/core/qgsrasterprojector.cpp > > > > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev > -- Best regards, Chaitanya kumar CH. /tʃaɪθənjə/ /kʊmɑr/ +91-9494447584 17.2416N 80.1426E
_______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
