[QGIS-trac] Re: [Quantum GIS] #2427: Can't build pyramids for IMG files

[Quantum GIS]

#2427: Can't build pyramids for IMG files
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        Reporter:  alexbruy                          |         Owner:  nobody       
            Type:  bug                               |        Status:  new          
        Priority:  major: does not work as expected  |     Milestone:  Version 1.5.0
       Component:  Rasters                           |       Version:  HEAD         
      Resolution:                                    |      Keywords:  pyramids, IMG
Platform_version:                                    |      Platform:  All          
        Must_fix:  No                                |   Status_info:  0            
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Comment (by alexbruy):

 I've test gdal from command line with landcover.img from the qgis sample
 dataset. Here is output
 of gdalinfo (no pyramids)
 {{{
  gdalinfo -nomd gis-samples/other/landcover.img
 Driver: HFA/Erdas Imagine Images (.img)
 Files: gis-samples/other/landcover.img
 Size is 3663, 1964
 ....
 Band 1 Block=64x64 Type=Byte, ColorInterp=Palette
   Description = Layer_1
   Color Table (RGB with 14 entries)
 }}}
 now build pyramids
 {{{
  gdaladdo -r average gis-samples/landcover.img 2 4 8 16 32
 0...10...20...30...40...50...60...70...80...90...100 - done.
 }}}
 and look with gdalinfo again

 {{{
  gdalinfo -nomd gis-samples/other/landcover.img
 Driver: HFA/Erdas Imagine Images (.img)
 Files: gis-samples/other/landcover.img
 Size is 3663, 1964
 ....
 Band 1 Block=64x64 Type=Byte, ColorInterp=Palette
   Description = Layer_1
   Overviews: 1832x982, 916x491, 458x246, 229x123, 115x62
   Color Table (RGB with 14 entries)
 }}}
 Pyramids was build. When this raster loaded in QGIS in properties all this
 pyramids are shows as active.

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Ticket URL: <http://trac.osgeo.org/qgis/ticket/2427#comment:2>
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