r.quantile1grass
Compute quantiles using two passes.
Usage
r.quantile
r.quantile --help
r.quantile [-r]
input=name
[quantiles=integer]
[percentiles=float
[,float, ...]]
[bins=integer]
[file=name]
[--overwrite]
[--help]
[--verbose]
[--quiet]
[--ui]
Keywords
raster, algebra, statistics, percentile, quantile
Overview
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.
Examples
Calculation of elevation quantiles (printed to standard-out):
g.region raster=elevation -pr.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 -pr.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
- •
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Engineering Statistics Handbook: Percentile, NIST
Source code
Available at: r.quantile source code (history)
Accessed: Monday Feb 24 17:50:47 2025
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© 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual
Releases
8 releases since Debian 6.0 (Squeeze); the text changed 7 times.