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 18:11:45 +0200 (Wed, 06 Oct 2010) $
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