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NAME

r.stats.quantile - Compute category quantiles using two passes.

KEYWORDS

raster, statistics, zonal statistics, percentile, quantile

SYNOPSIS

r.stats.quantile
r.stats.quantile --help
r.stats.quantile [-rpt] base=name cover=name [quantiles=integer] [percentiles=float[,float,...]] [bins=integer] [output=name[,name,...]] [file=name] [separator=character] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-r
Create reclass map with statistics as category labels
-p
Do not create output maps; just print statistics
-t
Print statistics in table format
--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:

base=name [required]
Name of base raster map
cover=name [required]
Name of cover raster map
quantiles=integer
Number of quantiles
percentiles=float[,float,...]
List of percentiles
Default: 50
bins=integer
Number of bins to use
Default: 1000
output=name[,name,...]
Resultant raster map(s)
file=name
Name for output file (if omitted or "-" output to stdout)
separator=character
Field separator
Special characters: pipe, comma, space, tab, newline
Default: :

Table of contents

DESCRIPTION

r.stats.quantile is a tool to analyse exploratory statistics of a floating-point "cover layer" according to how it intersects with objects in a "base layer". It provides quantile calculations as selected "zonal statistics".

NOTES

r.stats.quantile is intended to be a partial replacement for r.statistics, with support for floating-point cover maps. It provides quantile calculations, which are absent from r.stats.zonal.

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

EXAMPLE

In this example, the raster polygon map zipcodes in the North Carolina sample dataset is used to calculate quantile raster statistics using the elevation raster map:
g.region raster=zipcodes -p

# print quantiles
r.stats.quantile base=zipcodes cover=elevation quantiles=3 -p
27511:0:33.333333:134.717392
27511:1:66.666667:143.985723
27513:0:33.333333:140.669993
27513:1:66.666667:146.279449
27518:0:33.333333:115.140101
27518:1:66.666667:129.893723
[...]

# write out percentile raster maps
r.stats.quantile base=zipcodes cover=elevation percentiles=25,50,75 \
  output=zipcodes_elev_q25,zipcodes_elev_q50,zipcodes_elev_q75

REFERENCES

SEE ALSO

r.quantile, r.stats.zonal, r.statistics

AUTHORS

Glynn Clements
Markus Metz

SOURCE CODE

Available at: r.stats.quantile source code (history)

Latest change: Wednesday Apr 27 18:30:31 2022 in commit: 1ceca4dc48f005dfbfbc89b4cd9a998cd17a476f


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