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When I process a raster in QGIS it creates a second band. It appears that band has no useful data. I like to use the Raster Colours Tool and it will not accept a raster with anything more than on band. How do I remove the extra band?

many thanks in anticipation...

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What raster processing are you doing that creates the extra band? It sounds like it is generating a mask band. – MerseyViking Apr 25 '11 at 13:37
I am using the new clipper tool in QGIS 1.7. It is a GDAL_TRANSLATE implementation as far as I know. I use a shapefile mask layer and a no data value of 0. – BWill Apr 25 '11 at 14:46
up vote 5 down vote accepted

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.

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