Bug report #5858
Georeferencer ignores "Use 0 for transparency when needed" switch
|Affected QGIS version:||1.8.0||Regression?:||No|
|Operating System:||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:||no timely feedback|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||15323|
When I tick the "Use 0 for transparency when needed" and click "Start georeferencing" against an image that is rotated, I end up with a GeoTiff that has 3 bands, and black triangles in each corner. However, if I click "Generate GDAL script" and manually run the generated commands, a 4 band GeoTiff is created, with Band 4 as an alpha layer and the 4 corner triangles marked as transparent.
It seems that Georeferencer is not applying the -dstalpha flag when running gdalwarp (this is the only difference in the generated script when the "Use 0 for transparency when needed" is toggled).