r.quantile - Compute quantiles using two passes.

NAME  KEYWORDS  SYNOPSIS  Flags:  Parameters:  DESCRIPTION  NOTES  EXAMPLE  REFERENCES  SEE ALSO  AUTHORS  SOURCE CODE 

---

NAME

r.quantile − Compute quantiles using two passes.

KEYWORDS

raster, algebra, statistics, percentile, quantile

SYNOPSIS

r.quantile
r.quantile −−help
r.quantile [−r] input=name [quantiles=integer] [percentiles=float[,float,...]] [bins=integer] [file=name] [−−overwrite] [−−help] [−−verbose] [−−quiet] [−−ui]

Flags:

−r

Generate recode rules based on quantile−defined intervals

−−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]

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

file=name

Name for output file (if omitted or "−" output to stdout)

DESCRIPTION

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

NOTES

Quantiles are calculated following algorithm 7 from Hyndman and Fan (1996), which is also the default in R and numpy.

EXAMPLE

Calculation of elevation quantiles (printed to standard−out):

g.region raster=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 raster=elevation −p
r.quantile elevation quantiles=5 −r −−quiet | r.recode elevation \
           out=elev_quant5 rules=−

REFERENCES

	•		Hyndman and Fan (1996) Sample Quantiles in Statistical Packages, American Statistician. American Statistical Association. 50 (4): 361−365. DOI: 10.2307/2684934
	•		Engineering Statistics Handbook: Percentile, NIST

SEE ALSO

r.mode, r.quant, r.recode, r.series, r.stats, r.stats.quantile, r.stats.zonal, r.statistics, r.univar, v.rast.stats

AUTHORS

Glynn Clements
Markus Metz

SOURCE CODE

Available at: r.quantile source code (history)

Latest change: Thursday Jan 26 14:10:26 2023 in commit: cdd84c130cea04b204479e2efdc75c742efc4843

Main index | Raster index | Topics index | Keywords index | Graphical index | Full index

© 2003−2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual

---