1r.quantile(1)               GRASS GIS User's Manual              r.quantile(1)
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NAME

6       r.quantile  - Compute quantiles using two passes.
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KEYWORDS

9       raster, algebra, statistics, percentile, quantile
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SYNOPSIS

12       r.quantile
13       r.quantile --help
14       r.quantile     [-r]     input=name      [quantiles=integer]       [per‐
15       centiles=float[,float,...]]   [bins=integer]    [file=name]    [--over‐
16       write]  [--help]  [--verbose]  [--quiet]  [--ui]
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18   Flags:
19       -r
20           Generate recode rules based on quantile-defined intervals
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22       --overwrite
23           Allow output files to overwrite existing files
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25       --help
26           Print usage summary
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28       --verbose
29           Verbose module output
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31       --quiet
32           Quiet module output
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34       --ui
35           Force launching GUI dialog
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37   Parameters:
38       input=name [required]
39           Name of input raster map
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41       quantiles=integer
42           Number of quantiles
43           Default: 4
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45       percentiles=float[,float,...]
46           List of percentiles
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48       bins=integer
49           Number of bins to use
50           Default: 1000000
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52       file=name
53           Name for output file (if omitted or "-" output to stdout)
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DESCRIPTION

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

60       Quantiles are calculated following algorithm 7  from  Hyndman  and  Fan
61       (1996), which is also the default in R and numpy.
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EXAMPLE

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

73           •   Hyndman  and  Fan  (1996) Sample Quantiles in Statistical Pack‐
74               ages, American Statistician. American Statistical  Association.
75               50 (4): 361-365. DOI: 10.2307/2684934
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77           •   Engineering Statistics Handbook: Percentile, NIST
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SEE ALSO

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

84       Glynn Clements
85       Markus Metz
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SOURCE CODE

88       Available at: r.quantile source code (history)
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90       Accessed: Saturday Oct 28 18:17:51 2023
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92       Main index | Raster index | Topics index | Keywords index  |  Graphical
93       index | Full index
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95       © 2003-2023 GRASS Development Team, GRASS GIS 8.3.1 Reference Manual
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99GRASS 8.3.1                                                      r.quantile(1)
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