NAME

       r.rescale  - Rescales the range of category values in a raster map layer.

KEYWORDS

       raster, rescale

SYNOPSIS

       r.rescale
       r.rescale help
       r.rescale  [-q]  input=string   [from=min,max]  output=string to=min,max  [title="phrase"]
       [--overwrite]  [--verbose]  [--quiet]

   Flags:
       -q
           Quietly

       --overwrite
           Allow output files to overwrite existing files

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       input=string
           The name of the raster map to be rescaled

       from=min,max
           The input data range to be rescaled (default: full range of input map)

       output=string
           The resulting raster map name

       to=min,max
           The output data range

       title=
           Title for new raster map

DESCRIPTION

       The r.rescale program rescales the range of category values  appearing  in  a  raster  map
       layer.   A  new  raster  map layer, and an appropriate category file and color table based
       upon the original raster map layer, are generated with category labels  that  reflect  the
       original  category  values  that  produced  each  category.   This  command  is useful for
       producing representations with a reduced number of categories from a raster map layer with
       a  large  range of category values (e.g., elevation).  Rescaled map layers are appropriate
       for use in such GRASS programs as r.stats, r.report, and r.coin.

EXAMPLE

       To rescale an elevation raster map layer with category values ranging from 1090 meters  to
       1800  meters  into  the range 0-255, the following command line could be used (without the
       from parameter, the full value range will be used):
       r.rescale input=elevation from=1090,1800 output=elevation.255 to=0,255

NOTES

       Category values that fall beyond the input range will become NULL.  This allows  the  user
       to  select  a subset of the full category value range for rescaling if desired.  This also
       means that the user should know the category value range for the input raster  map  layer.
       The user can request the r.rescale program to determine this range, or can obtain it using
       the r.info command.  If the category value range is determined using r.rescale, the  input
       raster  map  layer  is  examined, and the minimum and maximum non-NULL category values are
       selected as the input range.

SEE ALSO

       r.coin, r.describe, r.info,  r.mapcalc,  r.reclass,  r.rescale.eq,  r.report,  r.resample,
       r.stats

AUTHOR

       Michael Shapiro, U.S.Army Construction Engineering Research Laboratory

       Last changed: $Date: 2010-10-06 09:11:45 -0700 (Wed, 06 Oct 2010) $

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       © 2003-2013 GRASS Development Team