[GRASS-dev] [GRASS GIS] #778: i.rgb.his, i.his.rgb: propagate NULLs

[GRASS GIS]

#778: i.rgb.his, i.his.rgb: propagate NULLs
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 Reporter:  hamish                |       Owner:  grass-dev@…              
     Type:  defect                |      Status:  new                      
 Priority:  major                 |   Milestone:  7.0.0                    
Component:  Raster                |     Version:  svn-trunk                
 Keywords:  i.rgb.his, i.his.rgb  |    Platform:  All                      
      Cpu:  Unspecified           |  
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Comment(by glynn):

 Replying to [comment:3 cmbarton]:
 > I agree about the 0-255 range. Can it simply be a setting, like in
 i.pca, with a default of 0,255 but changeable to a different min,max?

 It could be, but that's limited to a linear scale. Using the colour table
 is more flexible, although that limits you to 8-bit resolution.

 Probably the easiest solution is to just add a "divisor" option, which
 would default to 255 (or maybe to 1.0 for floating-point maps), and maybe
 a flag to use the colour table. That would allow for more than 8-bit
 resolution, and for floating-point maps using 0.0..1.0. If you want
 anything more complex (e.g. "gamma" law), you have to pre/post-process the
 maps with r.mapcalc.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/778#comment:10>
GRASS GIS <http://grass.osgeo.org>