When I add a satellite images as a raster in QGIS:
Why the image is changed, it looks like it has only one band?
Where is a tool for band combination?
Best Answer
I don't think the data are changed but I suspect that QGIS doesn't understand how to handle a multiband raster which has more than 3 bands so it defaults to gray-scale.
Once you have imported your raster, right-click on it and go to Layer Properties. In the style tab you have the option to render as a single band or three band (RGB) image. You can specify which bands to use for R, G and B and can tweak the min and max val
Interesting. If you specify a shapefile as a mask, it uses gdal_warp, and automatically adds -dstalpha to the commandline options.
For now, you could copy the text that appears at the bottom of the dialog box, and paste it into a command line window, removing the -dstalpha option. But this isn't an ideal solution, so I suggest you file a ticket on the QGIS bug tracker to get it added as an option.
As an alternative but sticking with the command line, you could run gdal_translate on your two-band file, using the option -b 1 to just use the first band for the output.
Band control is definitely something worth having in QGIS I reckon, so it might be worth adding that to the bug tracker as a requested feature.
In QGIS Desktop - use the Raster->Miscellaneous->Build Virtual Raster (Catalog) tool. Make sure to tick the "Separate" option. This will put each input file into a separate stacked band instead of mosaicing to a single band. If you used this tool already, this may be why you are getting a single band as output.
Best Answer
I don't think the data are changed but I suspect that QGIS doesn't understand how to handle a multiband raster which has more than 3 bands so it defaults to gray-scale.
Once you have imported your raster, right-click on it and go to Layer Properties. In the style tab you have the option to render as a single band or three band (RGB) image. You can specify which bands to use for R, G and B and can tweak the min and max val