On Sat, Feb 9, 2013 at 12:11 PM, Paul Meems <[email protected]> wrote: > Thanks Even, > > The low-res option really helped. Now I can test the commands in seconds > instead of hours. > I did these commands which seem to produce a tif file with overviews and > correct transparency. > I've opened it in MapWindow for now to check. MapWindow is using GDAL to > read raster files. > > I will now convert the hi-res version and try that version in Geoserver. > Here are the commands I used: > > # Create a low-res version: > gdal_translate my.ecw test\lowres.tif -outsize 1% 1% > > # Fix the almost white pixels: > nearblack -of GTiff -white -o lowres-white.tif lowres.tif > > > # Warp and mark white pixels as transparent > gdalwarp -multi -of GTiff -dstalpha -srcnodata "255 255 255" -co tiled=yes > -co "BLOCKXSIZE=512" -co "BLOCKYSIZE=512" -s_srs EPSG:28992 -r lanczos > -overwrite lowres-white.tif lowres-transparent.tif > > # Create internal tiles, don't use mask band because Geoserver doesn't like > that: > gdal_translate -of GTiff -a_srs EPSG:28992 -b 1 -b 2 -b 3 -co tiled=yes -co > compress=jpeg -co photometric=YCBCR -co BLOCKXSIZE=512 -co BLOCKYSIZE=512 > --config GDAL_TIFF_INTERNAL_MASK YES lowres-transparent.tif > lowres-compressed.tif > > # nodata is now black, but not all pixels are truly black: > nearblack -of GTiff -o lowres-compressed-black.tif lowres-compressed.tif > > # Set the nodata value to black: > gdal_translate -a_nodata 0 lowres-compressed-black.tif > lowres-compressed-transparent.tif
you need to add option to compress in these last two commands, or the final one only > > # Add overviews > gdaladdo -r average --config COMPRESS_OVERVIEW JPEG --config > PHOTOMETRIC_OVERVIEW YCBCR lowres-compressed-transparent.tif 2 4 8 16 32 64 > 128 > > > Thanks all. > > > Paul > > 2013/2/9 Even Rouault <[email protected]> >> >> Le samedi 09 février 2013 13:48:13, Paul Meems a écrit : >> > The last days I've been trying to convert my ecw file to a GeoTiff so I >> > can >> > use it in Geoserver. >> > The ecw is a mozaik of aerial photos. >> > When I do these two commands it is working in Geoserver: >> > >> > - gdal_translate -of GTiff -co tiled=yes -co compress=jpeg -co >> > photometric=YCBCR -a_srs EPSG:28992 -co "BLOCKXSIZE=512" -co >> > "BLOCKYSIZE=512" my.ecw my.tif >> > - gdaladdo -r average --config COMPRESS_OVERVIEW JPEG --config >> > PHOTOMETRIC_OVERVIEW YCBCR my.tif 2 4 8 16 32 64 128 >> > >> > But I want to add a second reference layer beneath this one which is >> > larger. The translated ecw has white edges, so that is not looking nice. >> > I've asked about this before and suggested was to use a cutline. So I >> > create a polygon that is inside the ecw file and ran this command: >> > >> > - gdalwarp -multi -cutline "clip.shp" -of GTiff -co tiled=yes -co >> > compress=jpeg -co photometric=YCBCR -co "BLOCKXSIZE=512" -co >> > "BLOCKYSIZE=512" -s_srs EPSG:28992 -r lanczos -overwrite my.ecw >> > clipped.tif >> > >> > When I open clipped.tif in MapWindow I can see the white edges are gone. >> > But when I call *gdaladdo* white artifacts are back again. >> >> I'm not clear why gdaladdo would add while artifacts if clipped.tif has no >> more white borders (i.e. if your clipping shape is a rectangle completely >> inside the validity area of the ECW). Unless clipped.tif has an alpha >> channel, >> but the gdalwarp command line you showed has no -dstalpha. But that >> wouldn't >> work actually since you use JPEG YCbCr compression, which doesn't support >> alpha channels. >> >> A solution - provided that MapWindows supports GDAL mask bands as >> transparency >> channels - would be : >> >> # Warp and mark white pixels as transparent >> gdalwarp 1.tif 2.tif -dstalpha -srcnodata "255 255 255" [other_options] >> >> # Transform 2.tif as a JPEG-YCBCR-in-TIFF with an internal mask band >> gdal_translate 2.tif 3.tif -b 1 -b 2 -b 3 -mask 4 -co compress=jpeg -co >> photometric=YCBCR -co BLOCKXSIZE=512 -co BLOCKYSIZE=512 --config >> GDAL_TIFF_INTERNAL_MASK YES >> >> # Add overviews >> gdaladdo 3.tif -r average --config COMPRESS_OVERVIEW JPEG --config >> PHOTOMETRIC_OVERVIEW YCBCR 2 4 >> >> > I'm now in the process of calling *nearblack* on both my.tiff and >> > clipped.tif but I'm not sure I'm doing it right. I think I'm using the >> > correct commands but perhaps in the wrong order. >> > The ecw file isn't very large (2.6GB) but all steps take a long time, >> > especially *nearblack *which is running for 4 hours now and is just at >> > 10%. >> > >> >> For the experiments, I'd encourage working with a low res extract of the >> ECW : >> gdal_translate src.ecw lowres.tif -outsize 1% 1% >> >> > Does anybody have some suggestions how to process the steps to convert >> > an >> > ecw file which has white outside areas to a transparent tif file with >> > overviews? >> > >> > I'm running the latest GDAL v1.10 version from Tamas on Windows Vista on >> > a >> > 8GB 4core machine. Speed is not a big issue when I know the result will >> > be >> > OK. >> >> Another point: It is well known that warping with compression doesn't >> produce >> files with optimal size. See >> http://trac.osgeo.org/gdal/wiki/UserDocs/GdalWarp#GeoTIFFoutput- >> coCOMPRESSisbroken >> >> > >> > Thanks, >> > >> > Paul > > > > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
