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r.resamp.stats

Resamples raster map layers to a coarser grid using aggregation.

r.resamp.stats [-nw] input=name output=name [method=string] [quantile=float] [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

r.resamp.stats input=name output=name

grass.script.run_command("r.resamp.stats", input, output, method="average", quantile=0.5, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("r.resamp.stats", input="name", output="name")

Parameters

input=name [required]
    Name of input raster map
output=name [required]
    Name for output raster map
method=string
    Aggregation method
    Allowed values: average, median, mode, minimum, maximum, range, quart1, quart3, perc90, sum, variance, stddev, quantile, count, diversity
    Default: average
quantile=float
    Quantile to calculate for method=quantile
    Allowed values: 0.0-1.0
    Default: 0.5
-n
    Propagate NULLs
-w
    Weight according to area (slower)
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

input : str, required
    Name of input raster map
    Used as: input, raster, name
output : str, required
    Name for output raster map
    Used as: output, raster, name
method : str, optional
    Aggregation method
    Allowed values: average, median, mode, minimum, maximum, range, quart1, quart3, perc90, sum, variance, stddev, quantile, count, diversity
    Default: average
quantile : float, optional
    Quantile to calculate for method=quantile
    Allowed values: 0.0-1.0
    Default: 0.5
flags : str, optional
    Allowed values: n, w
    n
        Propagate NULLs
    w
        Weight according to area (slower)
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

r.resamp.stats fills a grid cell (raster) matrix with aggregated values generated from a set of input layer data points.

Without the -w switch, the aggregate is computed over all of the input cells whose centers lie within the output cell.

With the -w switch, the aggregate uses the values from all input cells which intersect the output cell, weighted according to the proportion of the source cell which lies inside the output cell. This is slower, but produces a more accurate result.

NOTES

Resampling modules (r.resample, r.resamp.stats, r.resamp.interp, r.resamp.rst) resample the map to match the current region settings.

The notion of weighting doesn't make any sense for the min and max aggregates. However, the -w flag still has significance in that, when multiple destination cells overlap a source cell, the source cell is included in the calculation of all of the destination cells.

EXAMPLE

Resample elevation raster map to a lower resolution (from 6m to 20m; North Carolina sample dataset):

g.region raster=el_D782_6m -p
g.region res=20 -ap
# from 6m to 20m: weighted resampling -w
r.resamp.stats -w input=el_D782_6m output=el_D782_20m

GRASS r.resamp.stats result (subset)
Resampling of 6m DEM (left) to 20m DEM (right) with weighted resampling (subset)

SEE ALSO

g.region, r.resample, r.resamp.rst, r.resamp.filter, r.resamp.interp, r.neighbors

Overview: Interpolation and Resampling in GRASS GIS

Examples how statistical functions are applied can be found in the r.neighbors module documentation.

AUTHOR

Glynn Clements

SOURCE CODE

Available at: r.resamp.stats source code (history)
Latest change: Thursday Feb 13 11:55:34 2025 in commit ffc0b8c