## 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