i.his.rgb <main>      GRASS Reference Manual	 <main> i.his.rgb



NAME
     i.his.rgb - Hue-intensity-saturation (his) to red-green-blue
     (rgb) raster map color transformation function.
     (GRASS Image Processing Program)

SYNOPSIS
     i.his.rgb
     i.his.rgb help
     i.his.rgb hue_input=name intensity_input=name
     saturation_input=name
	  red_output=name green_output=name blue_output=name

DESCRIPTION
     i.his.rgb is an image processing program that processes
     three input raster map layers as hue, intensity and
     saturation components and produces three output raster map
     layers representing the red, green and blue components of
     this data.	 The output raster map layers are created by a
     standard hue-intensity-saturation (his) to red-green-blue
     (rgb) color transformation.  Each output raster map layer is
     given a linear gray scale color table.  The current
     geographic region and mask settings are respected.


     Parameters:

     hue_input=name	     Name of input raster map layer
			     representing hue.

     intensity_input=name    Name of input raster map layer
			     representing intensity.

     saturation_input=name   Name of input raster map layer
			     representing saturation.

     red_output=name	     Output raster map layer representing
			     the red component in the data.

     green_output=name	     Output raster map layer representing
			     the green component in the data.

     blue_output=name	     Output raster map layer representing
			     the blue component in the data.

NOTES
     It is not possible to process three bands with i.his.rgb and
     then exactly recover the original bands with i.rgb.his.
     This is due to loss of precision because of integer
     computations and rounding.	 Tests have shown that more than
     70% of the original cell values will be reproduced exactly
     after transformation in both directions and that 99% will be
     within plus or minus 1.  A few cell values may differ



GRASS 5.0beta6	      GRASS Development Team			1






i.his.rgb <main>      GRASS Reference Manual	 <main> i.his.rgb



     significantly from their original values.

SEE ALSO
     hsv.rgb.sh, i.colors, i.grey.scale, i.rgb.his, rgb.hsv.sh

AUTHOR
     David Satnik, GIS Laboratory, Central Washington University

     with acknowledgements to Ali Vali, Univ. of Texas Space
     Research Center, for the core routine.













































2		      GRASS Development Team	   GRASS 5.0beta6