Re: [gdal-dev] gtiff with internal mask
To solve the overviews I created an external mask file instead, in step 3, by removing the option --config GDAL_TIFF_INTERNAL_MASK YES from the command. As I am using GDAL 1.9.2 I don't know if this issue is caused by the solved issue in 1.10 (https://trac.osgeo.org/gdal/wiki/Release/1.10.0-News): When building overviews, if the image has already an internal mask, then build internal overviews for the mask implicitely I ended up with this set of files: Mosaic.tif Mosaic.tif.msk Mosaic.tif.msk.ovr Mosaic.tif.ovr And to use in qgis, corresponding to step 4: Mosaic_rgba_qgis.vrt Duarte -Mensagem original- De: Duarte Carreira Enviada: quinta-feira, 18 de Julho de 2013 13:01 Para: 'Even Rouault' Cc: 'gdal-dev@lists.osgeo.org' Assunto: RE: [gdal-dev] gtiff with internal mask So... now I 've got issues building the overviews. Gdaladdo loses the transparency so I get to see black areas where I was supposed to see nothing. When I zoom in black disappears. Any known way to overcome this? Thanks, Duarte -Mensagem original- De: Duarte Carreira Enviada: quarta-feira, 17 de Julho de 2013 19:41 Para: 'Even Rouault' Cc: gdal-dev@lists.osgeo.org Assunto: RE: [gdal-dev] gtiff with internal mask Well, you're right... I messed up recreating the footsteps... So, cleaning up: 1) create a rgba vrt using gdalwarp to cut the original mosaic with a shapefile gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 312 -co alpha=yes -dstalpha -cutline shapes\index_diss.shp -of vrt originalmosaic.vrt test_rgba_uncomp.vrt 2) create a masked uncompressed vrt using gdal_translate (because I couldn't compress right away, with errors of missing StripOffsets field) gdal_translate -b 1 -b 2 -b 3 -mask 4 -co alpha=no -co photometric=rgb -co interleave=pixel -co tiled=yes --config GDAL_TIFF_INTERNAL_MASK YES -of vrt test_rgba_uncomp.vrt testmask_uncomp.vrt 3) create final masked compressed tiff using gdal_translate gdal_translate -co alpha=no -co photometric=ycbcr -co interleave=pixel -co tiled=yes -co compress=jpeg --config GDAL_TIFF_INTERNAL_MASK YES testmask_uncomp.vrt test_finalmask.tif The power of VRT amazes me! Also regarding sizes: I still got the same ratio of 8x smaller. To use this in QGIS you still have to create a rgba vrt: 4) gdal_translate -of VRT -b 1 -b 2 -b 3 -b mask test_finalmask.tif test_finalmask_qgis.vrt (couldn't get the 4ª band to be recognized as an alpha band though) So I think now it's correct... I am going to apply this to a real-case mosaic and report back... Duarte -Mensagem original- De: Even Rouault [mailto:even.roua...@mines-paris.org] Enviada: quarta-feira, 17 de Julho de 2013 13:45 Para: Duarte Carreira Cc: gdal-dev@lists.osgeo.org Assunto: Re: [gdal-dev] gtiff with internal mask Le mercredi 17 juillet 2013 14:23:29, Duarte Carreira a écrit : Hi Even. Thanks so much for your tip! It works. I did have to specify I did not want an alpha band when cutting with the shapefile: gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 256 -co photometric=ycbcr -co compress=jpeg -co alpha=no --config GDAL_TIFF_INTERNAL_MASK YES -cutline shapes\index_diss.shp vrtini.vrt testmask.tif Hum, what I don't understand is how the above will produce a mask band in the output file... Does gdalinfo on testmask.tif show something like : Band 1 Block= Type=Byte, ColorInterp=Red Mask Flags: PER_DATASET Band 2 Block= Type=Byte, ColorInterp=Green Mask Flags: PER_DATASET Band 3 Block=... Type=Byte, ColorInterp=Blue Mask Flags: PER_DATASET I think you would need to do the above in 2 steps: 1) gdalwarp to an uncompressed RGBA TIFF 2) gdal_translate to turn the RGBA into a YCbCr JPEG-compressed GTiff + mask band Seems arcgis recognizes the masked tiff, but is much much slower displaying than using a normal alpha band. Perhaps adding -co TILED=YES will help ? (random guess) QGIS does need the vrt trick but then is as fast as usual. Also, the size is must smaller when using an internal mask: from a 219MB rgba,band interleaved,jpegd image to a 27MB ycbcr,pixel interleaved,jpegd masked tiff (8x smaller). Unless I missed something... Not completely surprising although more important than I would have expected. YCbCr compression usually gives a 2x to 3x compression bonus, and due to the usual nature of mask bands, the 1bit deflate compression of the mask band will give better results (both visually and in size) that the 8bit JPEG compression of the alpha band. Thanks again! Duarte -Mensagem original- De: Even Rouault [mailto:even.roua...@mines-paris.org] Enviada: terça-feira, 16 de Julho de 2013 18:58 Para: gdal-dev@lists.osgeo.org Cc: Duarte Carreira Assunto: Re: [gdal-dev] gtiff with internal mask Le mardi 16 juillet 2013 12:29:37, Duarte Carreira a écrit : I'm trying to create gtiffs with transparent areas where there are voids between my original images. I have successfully done it by using an alpha
Re: [gdal-dev] gtiff with internal mask
Please ignore previous email... should be a note to self... -Mensagem original- De: Duarte Carreira Enviada: sexta-feira, 19 de Julho de 2013 12:27 Para: 'Even Rouault' Cc: 'gdal-dev@lists.osgeo.org' Assunto: RE: [gdal-dev] gtiff with internal mask Ok, para conseguir construir as pirâmides temos de ter a máscara separada e não incluída no próprio tiff. Para isso basta alterar o 3º passo que cria efectivamente o tiff a partir do vrt, removendo a opção de criar a máscara interna, ficando assim: gdal_translate -co alpha=no -co photometric=ycbcr -co interleave=pixel -co tiled=yes -co compress=jpeg testmask_uncomp.vrt test_finalmask.tif Isto basta para que seja criado um tif rgb e um ficheiro .msk separados. *** Para criar um rgb+iv num só tiff, com máscara! *** Alterar o mosaico vrt criado no 2º passo, que já inclui a máscara, e criar uma banda Gray com origem no mosaico vrt dos infravermelhos. Depois é só converter mas usando as opções: -co alpha=no -co photometric=rgb e talvez -co interleave=band (para não dar erro). Não podemos usar ycbcr porque só dá para 3 bandas e nós temos 4. DC -Mensagem original- De: Duarte Carreira Enviada: quinta-feira, 18 de Julho de 2013 13:01 Para: 'Even Rouault' Cc: 'gdal-dev@lists.osgeo.org' Assunto: RE: [gdal-dev] gtiff with internal mask So... now I 've got issues building the overviews. Gdaladdo loses the transparency so I get to see black areas where I was supposed to see nothing. When I zoom in black disappears. Any known way to overcome this? Thanks, Duarte -Mensagem original- De: Duarte Carreira Enviada: quarta-feira, 17 de Julho de 2013 19:41 Para: 'Even Rouault' Cc: gdal-dev@lists.osgeo.org Assunto: RE: [gdal-dev] gtiff with internal mask Well, you're right... I messed up recreating the footsteps... So, cleaning up: 1) create a rgba vrt using gdalwarp to cut the original mosaic with a shapefile gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 312 -co alpha=yes -dstalpha -cutline shapes\index_diss.shp -of vrt originalmosaic.vrt test_rgba_uncomp.vrt 2) create a masked uncompressed vrt using gdal_translate (because I couldn't compress right away, with errors of missing StripOffsets field) gdal_translate -b 1 -b 2 -b 3 -mask 4 -co alpha=no -co photometric=rgb -co interleave=pixel -co tiled=yes --config GDAL_TIFF_INTERNAL_MASK YES -of vrt test_rgba_uncomp.vrt testmask_uncomp.vrt 3) create final masked compressed tiff using gdal_translate gdal_translate -co alpha=no -co photometric=ycbcr -co interleave=pixel -co tiled=yes -co compress=jpeg --config GDAL_TIFF_INTERNAL_MASK YES testmask_uncomp.vrt test_finalmask.tif The power of VRT amazes me! Also regarding sizes: I still got the same ratio of 8x smaller. To use this in QGIS you still have to create a rgba vrt: 4) gdal_translate -of VRT -b 1 -b 2 -b 3 -b mask test_finalmask.tif test_finalmask_qgis.vrt (couldn't get the 4ª band to be recognized as an alpha band though) So I think now it's correct... I am going to apply this to a real-case mosaic and report back... Duarte -Mensagem original- De: Even Rouault [mailto:even.roua...@mines-paris.org] Enviada: quarta-feira, 17 de Julho de 2013 13:45 Para: Duarte Carreira Cc: gdal-dev@lists.osgeo.org Assunto: Re: [gdal-dev] gtiff with internal mask Le mercredi 17 juillet 2013 14:23:29, Duarte Carreira a écrit : Hi Even. Thanks so much for your tip! It works. I did have to specify I did not want an alpha band when cutting with the shapefile: gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 256 -co photometric=ycbcr -co compress=jpeg -co alpha=no --config GDAL_TIFF_INTERNAL_MASK YES -cutline shapes\index_diss.shp vrtini.vrt testmask.tif Hum, what I don't understand is how the above will produce a mask band in the output file... Does gdalinfo on testmask.tif show something like : Band 1 Block= Type=Byte, ColorInterp=Red Mask Flags: PER_DATASET Band 2 Block= Type=Byte, ColorInterp=Green Mask Flags: PER_DATASET Band 3 Block=... Type=Byte, ColorInterp=Blue Mask Flags: PER_DATASET I think you would need to do the above in 2 steps: 1) gdalwarp to an uncompressed RGBA TIFF 2) gdal_translate to turn the RGBA into a YCbCr JPEG-compressed GTiff + mask band Seems arcgis recognizes the masked tiff, but is much much slower displaying than using a normal alpha band. Perhaps adding -co TILED=YES will help ? (random guess) QGIS does need the vrt trick but then is as fast as usual. Also, the size is must smaller when using an internal mask: from a 219MB rgba,band interleaved,jpegd image to a 27MB ycbcr,pixel interleaved,jpegd masked tiff (8x smaller). Unless I missed something... Not completely surprising although more important than I would have expected. YCbCr compression usually gives a 2x to 3x compression bonus, and due to the usual nature of mask bands, the 1bit deflate compression of the mask band will give better results (both visually and in size) that the 8bit
Re: [gdal-dev] gtiff with internal mask
Ok, para conseguir construir as pirâmides temos de ter a máscara separada e não incluída no próprio tiff. Para isso basta alterar o 3º passo que cria efectivamente o tiff a partir do vrt, removendo a opção de criar a máscara interna, ficando assim: gdal_translate -co alpha=no -co photometric=ycbcr -co interleave=pixel -co tiled=yes -co compress=jpeg testmask_uncomp.vrt test_finalmask.tif Isto basta para que seja criado um tif rgb e um ficheiro .msk separados. *** Para criar um rgb+iv num só tiff, com máscara! *** Alterar o mosaico vrt criado no 2º passo, que já inclui a máscara, e criar uma banda Gray com origem no mosaico vrt dos infravermelhos. Depois é só converter mas usando as opções: -co alpha=no -co photometric=rgb e talvez -co interleave=band (para não dar erro). Não podemos usar ycbcr porque só dá para 3 bandas e nós temos 4. DC -Mensagem original- De: Duarte Carreira Enviada: quinta-feira, 18 de Julho de 2013 13:01 Para: 'Even Rouault' Cc: 'gdal-dev@lists.osgeo.org' Assunto: RE: [gdal-dev] gtiff with internal mask So... now I 've got issues building the overviews. Gdaladdo loses the transparency so I get to see black areas where I was supposed to see nothing. When I zoom in black disappears. Any known way to overcome this? Thanks, Duarte -Mensagem original- De: Duarte Carreira Enviada: quarta-feira, 17 de Julho de 2013 19:41 Para: 'Even Rouault' Cc: gdal-dev@lists.osgeo.org Assunto: RE: [gdal-dev] gtiff with internal mask Well, you're right... I messed up recreating the footsteps... So, cleaning up: 1) create a rgba vrt using gdalwarp to cut the original mosaic with a shapefile gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 312 -co alpha=yes -dstalpha -cutline shapes\index_diss.shp -of vrt originalmosaic.vrt test_rgba_uncomp.vrt 2) create a masked uncompressed vrt using gdal_translate (because I couldn't compress right away, with errors of missing StripOffsets field) gdal_translate -b 1 -b 2 -b 3 -mask 4 -co alpha=no -co photometric=rgb -co interleave=pixel -co tiled=yes --config GDAL_TIFF_INTERNAL_MASK YES -of vrt test_rgba_uncomp.vrt testmask_uncomp.vrt 3) create final masked compressed tiff using gdal_translate gdal_translate -co alpha=no -co photometric=ycbcr -co interleave=pixel -co tiled=yes -co compress=jpeg --config GDAL_TIFF_INTERNAL_MASK YES testmask_uncomp.vrt test_finalmask.tif The power of VRT amazes me! Also regarding sizes: I still got the same ratio of 8x smaller. To use this in QGIS you still have to create a rgba vrt: 4) gdal_translate -of VRT -b 1 -b 2 -b 3 -b mask test_finalmask.tif test_finalmask_qgis.vrt (couldn't get the 4ª band to be recognized as an alpha band though) So I think now it's correct... I am going to apply this to a real-case mosaic and report back... Duarte -Mensagem original- De: Even Rouault [mailto:even.roua...@mines-paris.org] Enviada: quarta-feira, 17 de Julho de 2013 13:45 Para: Duarte Carreira Cc: gdal-dev@lists.osgeo.org Assunto: Re: [gdal-dev] gtiff with internal mask Le mercredi 17 juillet 2013 14:23:29, Duarte Carreira a écrit : Hi Even. Thanks so much for your tip! It works. I did have to specify I did not want an alpha band when cutting with the shapefile: gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 256 -co photometric=ycbcr -co compress=jpeg -co alpha=no --config GDAL_TIFF_INTERNAL_MASK YES -cutline shapes\index_diss.shp vrtini.vrt testmask.tif Hum, what I don't understand is how the above will produce a mask band in the output file... Does gdalinfo on testmask.tif show something like : Band 1 Block= Type=Byte, ColorInterp=Red Mask Flags: PER_DATASET Band 2 Block= Type=Byte, ColorInterp=Green Mask Flags: PER_DATASET Band 3 Block=... Type=Byte, ColorInterp=Blue Mask Flags: PER_DATASET I think you would need to do the above in 2 steps: 1) gdalwarp to an uncompressed RGBA TIFF 2) gdal_translate to turn the RGBA into a YCbCr JPEG-compressed GTiff + mask band Seems arcgis recognizes the masked tiff, but is much much slower displaying than using a normal alpha band. Perhaps adding -co TILED=YES will help ? (random guess) QGIS does need the vrt trick but then is as fast as usual. Also, the size is must smaller when using an internal mask: from a 219MB rgba,band interleaved,jpegd image to a 27MB ycbcr,pixel interleaved,jpegd masked tiff (8x smaller). Unless I missed something... Not completely surprising although more important than I would have expected. YCbCr compression usually gives a 2x to 3x compression bonus, and due to the usual nature of mask bands, the 1bit deflate compression of the mask band will give better results (both visually and in size) that the 8bit JPEG compression of the alpha band. Thanks again! Duarte -Mensagem original- De: Even Rouault [mailto:even.roua...@mines-paris.org] Enviada: terça-feira, 16 de Julho de 2013 18:58 Para: gdal-dev@lists.osgeo.org Cc: Duarte Carreira
Re: [gdal-dev] gtiff with internal mask
So... now I 've got issues building the overviews. Gdaladdo loses the transparency so I get to see black areas where I was supposed to see nothing. When I zoom in black disappears. Any known way to overcome this? Thanks, Duarte -Mensagem original- De: Duarte Carreira Enviada: quarta-feira, 17 de Julho de 2013 19:41 Para: 'Even Rouault' Cc: gdal-dev@lists.osgeo.org Assunto: RE: [gdal-dev] gtiff with internal mask Well, you're right... I messed up recreating the footsteps... So, cleaning up: 1) create a rgba vrt using gdalwarp to cut the original mosaic with a shapefile gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 312 -co alpha=yes -dstalpha -cutline shapes\index_diss.shp -of vrt originalmosaic.vrt test_rgba_uncomp.vrt 2) create a masked uncompressed vrt using gdal_translate (because I couldn't compress right away, with errors of missing StripOffsets field) gdal_translate -b 1 -b 2 -b 3 -mask 4 -co alpha=no -co photometric=rgb -co interleave=pixel -co tiled=yes --config GDAL_TIFF_INTERNAL_MASK YES -of vrt test_rgba_uncomp.vrt testmask_uncomp.vrt 3) create final masked compressed tiff using gdal_translate gdal_translate -co alpha=no -co photometric=ycbcr -co interleave=pixel -co tiled=yes -co compress=jpeg --config GDAL_TIFF_INTERNAL_MASK YES testmask_uncomp.vrt test_finalmask.tif The power of VRT amazes me! Also regarding sizes: I still got the same ratio of 8x smaller. To use this in QGIS you still have to create a rgba vrt: 4) gdal_translate -of VRT -b 1 -b 2 -b 3 -b mask test_finalmask.tif test_finalmask_qgis.vrt (couldn't get the 4ª band to be recognized as an alpha band though) So I think now it's correct... I am going to apply this to a real-case mosaic and report back... Duarte -Mensagem original- De: Even Rouault [mailto:even.roua...@mines-paris.org] Enviada: quarta-feira, 17 de Julho de 2013 13:45 Para: Duarte Carreira Cc: gdal-dev@lists.osgeo.org Assunto: Re: [gdal-dev] gtiff with internal mask Le mercredi 17 juillet 2013 14:23:29, Duarte Carreira a écrit : Hi Even. Thanks so much for your tip! It works. I did have to specify I did not want an alpha band when cutting with the shapefile: gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 256 -co photometric=ycbcr -co compress=jpeg -co alpha=no --config GDAL_TIFF_INTERNAL_MASK YES -cutline shapes\index_diss.shp vrtini.vrt testmask.tif Hum, what I don't understand is how the above will produce a mask band in the output file... Does gdalinfo on testmask.tif show something like : Band 1 Block= Type=Byte, ColorInterp=Red Mask Flags: PER_DATASET Band 2 Block= Type=Byte, ColorInterp=Green Mask Flags: PER_DATASET Band 3 Block=... Type=Byte, ColorInterp=Blue Mask Flags: PER_DATASET I think you would need to do the above in 2 steps: 1) gdalwarp to an uncompressed RGBA TIFF 2) gdal_translate to turn the RGBA into a YCbCr JPEG-compressed GTiff + mask band Seems arcgis recognizes the masked tiff, but is much much slower displaying than using a normal alpha band. Perhaps adding -co TILED=YES will help ? (random guess) QGIS does need the vrt trick but then is as fast as usual. Also, the size is must smaller when using an internal mask: from a 219MB rgba,band interleaved,jpegd image to a 27MB ycbcr,pixel interleaved,jpegd masked tiff (8x smaller). Unless I missed something... Not completely surprising although more important than I would have expected. YCbCr compression usually gives a 2x to 3x compression bonus, and due to the usual nature of mask bands, the 1bit deflate compression of the mask band will give better results (both visually and in size) that the 8bit JPEG compression of the alpha band. Thanks again! Duarte -Mensagem original- De: Even Rouault [mailto:even.roua...@mines-paris.org] Enviada: terça-feira, 16 de Julho de 2013 18:58 Para: gdal-dev@lists.osgeo.org Cc: Duarte Carreira Assunto: Re: [gdal-dev] gtiff with internal mask Le mardi 16 juillet 2013 12:29:37, Duarte Carreira a écrit : I'm trying to create gtiffs with transparent areas where there are voids between my original images. I have successfully done it by using an alpha band but this process created 3x larger images. I think partly because of an additional 4th band and partly because I cannot use ycbcr to compress with jpeg. So I thought of using internal masks expecting to get smaller images but cannot get it to work. When converting from the rgba image using -mask 4 I cannot see the transparency and get black areas: gdal_translate -b 1 -b 2 -b 3 -ma sk 4 --config GDAL_TIFF_INTERNAL_MASK YES test_alpha.tif test_internalmask.tif I tried looking at the images using qgis and paint.net. I know QGIS doesn't use the GDALGetMaskBand() API, so no real surprise (that would likely be a possible QGIS enhancement). And paint.net probably doesn't support this feature of the TIFF format either. MapServer does support mask
Re: [gdal-dev] gtiff with internal mask
Hi Even. Thanks so much for your tip! It works. I did have to specify I did not want an alpha band when cutting with the shapefile: gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 256 -co photometric=ycbcr -co compress=jpeg -co alpha=no --config GDAL_TIFF_INTERNAL_MASK YES -cutline shapes\index_diss.shp vrtini.vrt testmask.tif Seems arcgis recognizes the masked tiff, but is much much slower displaying than using a normal alpha band. QGIS does need the vrt trick but then is as fast as usual. Also, the size is must smaller when using an internal mask: from a 219MB rgba,band interleaved,jpegd image to a 27MB ycbcr,pixel interleaved,jpegd masked tiff (8x smaller). Unless I missed something... Thanks again! Duarte -Mensagem original- De: Even Rouault [mailto:even.roua...@mines-paris.org] Enviada: terça-feira, 16 de Julho de 2013 18:58 Para: gdal-dev@lists.osgeo.org Cc: Duarte Carreira Assunto: Re: [gdal-dev] gtiff with internal mask Le mardi 16 juillet 2013 12:29:37, Duarte Carreira a écrit : I'm trying to create gtiffs with transparent areas where there are voids between my original images. I have successfully done it by using an alpha band but this process created 3x larger images. I think partly because of an additional 4th band and partly because I cannot use ycbcr to compress with jpeg. So I thought of using internal masks expecting to get smaller images but cannot get it to work. When converting from the rgba image using -mask 4 I cannot see the transparency and get black areas: gdal_translate -b 1 -b 2 -b 3 -ma sk 4 --config GDAL_TIFF_INTERNAL_MASK YES test_alpha.tif test_internalmask.tif I tried looking at the images using qgis and paint.net. I know QGIS doesn't use the GDALGetMaskBand() API, so no real surprise (that would likely be a possible QGIS enhancement). And paint.net probably doesn't support this feature of the TIFF format either. MapServer does support mask bands however. For QGIS, you could workaround that however. Imagine that you have a YCbCr TIFF + internal mask in.tif. You can do : gdal_translate -of VRT -b 1 -b 2 -b 3 -b mask in.tif out.vrt And QGIS should handle out.vrt as a regular RGBA dataset. Any hints or help appreciated. Thanks, Duarte Duarte Carreira Diretor | Dep. Informa??o Geogr?fica e Cartografia www.edia.pthttp://www.edia.pt www.alqueva.com.pthttp://www.alqueva.com.pt Tel. +351 284315100 [http://www.edia.pt/edia/images/edia_logo2.gif]http://www.edia.pt -- Geospatial professional services http://even.rouault.free.fr/services.html ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] gtiff with internal mask
Well, you're right... I messed up recreating the footsteps... So, cleaning up: 1) create a rgba vrt using gdalwarp to cut the original mosaic with a shapefile gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 312 -co alpha=yes -dstalpha -cutline shapes\index_diss.shp -of vrt originalmosaic.vrt test_rgba_uncomp.vrt 2) create a masked uncompressed vrt using gdal_translate (because I couldn't compress right away, with errors of missing StripOffsets field) gdal_translate -b 1 -b 2 -b 3 -mask 4 -co alpha=no -co photometric=rgb -co interleave=pixel -co tiled=yes --config GDAL_TIFF_INTERNAL_MASK YES -of vrt test_rgba_uncomp.vrt testmask_uncomp.vrt 3) create final masked compressed tiff using gdal_translate gdal_translate -co alpha=no -co photometric=ycbcr -co interleave=pixel -co tiled=yes -co compress=jpeg --config GDAL_TIFF_INTERNAL_MASK YES testmask_uncomp.vrt test_finalmask.tif The power of VRT amazes me! Also regarding sizes: I still got the same ratio of 8x smaller. To use this in QGIS you still have to create a rgba vrt: 4) gdal_translate -of VRT -b 1 -b 2 -b 3 -b mask test_finalmask.tif test_finalmask_qgis.vrt (couldn't get the 4ª band to be recognized as an alpha band though) So I think now it's correct... I am going to apply this to a real-case mosaic and report back... Duarte -Mensagem original- De: Even Rouault [mailto:even.roua...@mines-paris.org] Enviada: quarta-feira, 17 de Julho de 2013 13:45 Para: Duarte Carreira Cc: gdal-dev@lists.osgeo.org Assunto: Re: [gdal-dev] gtiff with internal mask Le mercredi 17 juillet 2013 14:23:29, Duarte Carreira a écrit : Hi Even. Thanks so much for your tip! It works. I did have to specify I did not want an alpha band when cutting with the shapefile: gdalwarp -multi -wm 480 --config GDAL_CACHEMAX 256 -co photometric=ycbcr -co compress=jpeg -co alpha=no --config GDAL_TIFF_INTERNAL_MASK YES -cutline shapes\index_diss.shp vrtini.vrt testmask.tif Hum, what I don't understand is how the above will produce a mask band in the output file... Does gdalinfo on testmask.tif show something like : Band 1 Block= Type=Byte, ColorInterp=Red Mask Flags: PER_DATASET Band 2 Block= Type=Byte, ColorInterp=Green Mask Flags: PER_DATASET Band 3 Block=... Type=Byte, ColorInterp=Blue Mask Flags: PER_DATASET I think you would need to do the above in 2 steps: 1) gdalwarp to an uncompressed RGBA TIFF 2) gdal_translate to turn the RGBA into a YCbCr JPEG-compressed GTiff + mask band Seems arcgis recognizes the masked tiff, but is much much slower displaying than using a normal alpha band. Perhaps adding -co TILED=YES will help ? (random guess) QGIS does need the vrt trick but then is as fast as usual. Also, the size is must smaller when using an internal mask: from a 219MB rgba,band interleaved,jpegd image to a 27MB ycbcr,pixel interleaved,jpegd masked tiff (8x smaller). Unless I missed something... Not completely surprising although more important than I would have expected. YCbCr compression usually gives a 2x to 3x compression bonus, and due to the usual nature of mask bands, the 1bit deflate compression of the mask band will give better results (both visually and in size) that the 8bit JPEG compression of the alpha band. Thanks again! Duarte -Mensagem original- De: Even Rouault [mailto:even.roua...@mines-paris.org] Enviada: terça-feira, 16 de Julho de 2013 18:58 Para: gdal-dev@lists.osgeo.org Cc: Duarte Carreira Assunto: Re: [gdal-dev] gtiff with internal mask Le mardi 16 juillet 2013 12:29:37, Duarte Carreira a écrit : I'm trying to create gtiffs with transparent areas where there are voids between my original images. I have successfully done it by using an alpha band but this process created 3x larger images. I think partly because of an additional 4th band and partly because I cannot use ycbcr to compress with jpeg. So I thought of using internal masks expecting to get smaller images but cannot get it to work. When converting from the rgba image using -mask 4 I cannot see the transparency and get black areas: gdal_translate -b 1 -b 2 -b 3 -ma sk 4 --config GDAL_TIFF_INTERNAL_MASK YES test_alpha.tif test_internalmask.tif I tried looking at the images using qgis and paint.net. I know QGIS doesn't use the GDALGetMaskBand() API, so no real surprise (that would likely be a possible QGIS enhancement). And paint.net probably doesn't support this feature of the TIFF format either. MapServer does support mask bands however. For QGIS, you could workaround that however. Imagine that you have a YCbCr TIFF + internal mask in.tif. You can do : gdal_translate -of VRT -b 1 -b 2 -b 3 -b mask in.tif out.vrt And QGIS should handle out.vrt as a regular RGBA dataset. Any hints or help appreciated. Thanks, Duarte Duarte Carreira Diretor | Dep. Informa??o Geogr?fica e Cartografia
