r.stats.quantile.1grass - Man Page

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: :

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)

Accessed: Wednesday Jan 24 21:12:45 2024

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