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    input=name     [from=min,max]     output=name    to=min,max    [title=phrase]
       [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       --overwrite
           Allow output files to overwrite existing files

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       input=name [required]
           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=name [required]
           The resulting raster map name

       to=min,max [required]
           The output data range

       title=phrase
           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 GIS commands 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.describe or 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: 2014-12-09 19:46:50 +0100 (Tue, 09 Dec 2014) $

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