NAME

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

KEYWORDS

       raster, rescale

SYNOPSIS

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

   Flags:
       -q
           Quiet

       --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.eq  program rescales the range of category values appearing in a raster map
       layer with equalized histogram.  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.eq 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.eq 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.eq, 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, 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