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) $

       Full index

       © 2003-2013 GRASS Development Team

GRASS 6.4.3                                                                                 r.rescale.eq(1grass)