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NAME

r.quantile - Compute quantiles using two passes.

KEYWORDS

raster, statistics

SYNOPSIS

r.quantile
r.quantile help
r.quantile [-r] input=name [quantiles=integer] [percentiles=float[,float,...]] [bins=integer] [--verbose] [--quiet]

Flags:

-r
Generate recode rules based on quantile-defined intervals
--verbose
Verbose module output
--quiet
Quiet module output

Parameters:

input=name
Name of input raster map
quantiles=integer
Number of quantiles
Default: 4
percentiles=float[,float,...]
List of percentiles
bins=integer
Number of bins to use
Default: 1000000

DESCRIPTION

r.quantile computes quantiles in a manner suitable for use with large amounts of data. It is using two passes.

EXAMPLE

Calculation of elevation quantiles (printed to standard-out):
g.region rast=elevation -p
r.quantile input=elevation percentiles=0.1,1,10,25,50,75,90,99,99.9
The output of r.quantile can be used for quantile classification:
g.region rast=elevation -p
r.quantile elevation quantiles=5 -r --quiet | r.recode elevation \
           out=elev_quant5 rules=-

SEE ALSO

r.quant

AUTHOR

Glynn Clements

Last changed: $Date: 2013-04-10 08:52:37 -0700 (Wed, 10 Apr 2013) $


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