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 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.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 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.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

SOURCE CODE

       Available at: r.rescale.eq source code (history)

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual