r.quantile.ref - GRASS GIS manual

Note: This addon document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade your GRASS GIS installation, and read the current addon manual page.

NAME

r.quantile.ref - Determines quantile for input value from reference raster map layers.

KEYWORDS

raster, aggregation, series, statistics, quantile

SYNOPSIS

r.quantile.ref

r.quantile.ref --help

r.quantile.ref [-z] input=name [reference=name[,name,...]] [file=name] output=name [range=lo,hi] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-z: Do not keep files open
--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:

input=name [required]: Name of input raster map
reference=name[,name,...]: List ofreference raster maps
file=name: Input file with one reference raster map name per line
output=name [required]: Name for output raster map
range=lo,hi: Ignore values outside this range

DESCRIPTION
EXAMPLE
SEE ALSO
AUTHOR

DESCRIPTION

r.quantile.ref computes for each pixel the quantile ranking of the input value against the reference maps: values of 0, 0.5 and 1.0 respectively indicate that the input value corresponds with the minimum, median or maximum of the reference values. A value of -1 is assigned if the input value is smaller than the minimum and a value of 2 is assigned if the input value is larger than the maximum.

r.quantile.ref can be regarded as the inverse of r.series method=quantile: while r.series calculates the value for a given quantile, r.quantile.ref calculates the quantile for a given value. This is useful to compare e.g. current environmental conditions to a time series of historical environmental conditions.

EXAMPLE

Create some reference rasters:

r.mapcalc "ref1 = 1"
r.mapcalc "ref2 = 2"
r.mapcalc "ref3 = 3"
r.mapcalc "ref4 = 5"
r.mapcalc "ref5 = 5"
r.mapcalc "ref6 = 5"

Create a test raster with cell value 4.5:

r.mapcalc "test = 4.5"

Get the quantile of the test raster for the reference maps:

r.quantile.ref input=test reference=ref1,ref2,ref3,ref4,ref5,ref6 output=test_quant

The quantile corresponding to the value 4.5 is 0.55. Create a test raster with cell value 5:

r.mapcalc "test = 5"

Get the quantile of the test raster for the reference maps:

r.quantile.ref input=test reference=ref1,ref2,ref3,ref4,ref5,ref6 output=test_quant

The quantile corresponding to the value 5 is 0.8.

AUTHOR

Markus Metz

SOURCE CODE

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

Latest change: Mon Jun 28 07:54:09 2021 in commit: 1cfc0af029a35a5d6c7dae5ca7204d0eb85dbc55