Re: [Qgis-user] QGIS Georeferencer and Transparency
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Il 13/01/2014 22:05, Jukka Rahkonen ha scritto: > Don't let QGIS to do the warping but just push the button and create the > GDAL commands. Then you can edit the gdal_translate command and have total > control over all the features it supports http://www.gdal.org/gdalwarp.html. > You may be able to set -dstnodata to some value that does not exist in your > data, for example "0 0 255" for total blue. Or then you can add alpha > channel with -dstalpha. I think this recipe should not be lost. Ho about adding it to the manual, probably with an "Advanced" flag? > Unfortunately you can't edit the command and run it as edited directly from > the georeferencer but you must run it in a separete GDAL command window. this shouldn't be difficult to add. All the best. - -- Paolo Cavallini - www.faunalia.eu Corsi QGIS e PostGIS: http://www.faunalia.eu/training.html -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: Using GnuPG with Icedove - http://www.enigmail.net/ iEYEARECAAYFAlLU2p8ACgkQ/NedwLUzIr4cTQCbBJCub5CRb1JQqu0XxvdRwwWA eLkAn3ZcoVw32Ts+C75G3QNKrJPpJfiR =zQEQ -END PGP SIGNATURE- ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] QGIS Georeferencer and Transparency
Andreas Neumann writes: > > Hi, > > Some of my maps I georeference are rotated approx. 45 degrees because > they did not point to the north before georeferencing. This is desired - > however - the resulting file has a huge black background as a result of > the rotation. > > I tried with the option "use 0 for transparency if necessary" - which > helped - but the map already contains black pixels and the result is > that I have a lot of tiny transparent pixels in the map, next to the > transparent background I wanted. Is there a way to set this transparency > to a custom RGB value that I know it is not yet used within the map? Hi, Don't let QGIS to do the warping but just push the button and create the GDAL commands. Then you can edit the gdal_translate command and have total control over all the features it supports http://www.gdal.org/gdalwarp.html. You may be able to set -dstnodata to some value that does not exist in your data, for example "0 0 255" for total blue. Or then you can add alpha channel with -dstalpha. Unfortunately you can't edit the command and run it as edited directly from the georeferencer but you must run it in a separete GDAL command window. -Jukka Rahkonen- ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] QGIS Georeferencer and Transparency
I had the same issue, but with a mosaic image, and edited the source rasters with Gimp to make black pixels slightly lighter. Not noticeable in the image but enough to not be transparent. On Jan 8, 2014 12:25 AM, "Andreas Neumann" wrote: > Hi, > > Some of my maps I georeference are rotated approx. 45 degrees because > they did not point to the north before georeferencing. This is desired - > however - the resulting file has a huge black background as a result of > the rotation. > > I tried with the option "use 0 for transparency if necessary" - which > helped - but the map already contains black pixels and the result is > that I have a lot of tiny transparent pixels in the map, next to the > transparent background I wanted. Is there a way to set this transparency > to a custom RGB value that I know it is not yet used within the map? > > Thank you for any ideas. > > Andreas > ___ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/qgis-user > ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] QGIS Georeferencer and Transparency
Dear Andreas, try Raster | Extraction | Clipper with a mask layer and alpha band. Regards, Zoltan On Tue, 7 Jan 2014, Andreas Neumann wrote: Hi, Some of my maps I georeference are rotated approx. 45 degrees because they did not point to the north before georeferencing. This is desired - however - the resulting file has a huge black background as a result of the rotation. I tried with the option "use 0 for transparency if necessary" - which helped - but the map already contains black pixels and the result is that I have a lot of tiny transparent pixels in the map, next to the transparent background I wanted. Is there a way to set this transparency to a custom RGB value that I know it is not yet used within the map? Thank you for any ideas. Andreas ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
[Qgis-user] QGIS Georeferencer and Transparency
Hi, Some of my maps I georeference are rotated approx. 45 degrees because they did not point to the north before georeferencing. This is desired - however - the resulting file has a huge black background as a result of the rotation. I tried with the option "use 0 for transparency if necessary" - which helped - but the map already contains black pixels and the result is that I have a lot of tiny transparent pixels in the map, next to the transparent background I wanted. Is there a way to set this transparency to a custom RGB value that I know it is not yet used within the map? Thank you for any ideas. Andreas ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
