NAME¶
r.resamp.stats - Resamples raster map layers to a coarser grid
using aggregation.
KEYWORDS¶
raster, resample
SYNOPSIS¶
r.resamp.stats
r.resamp.stats help
r.resamp.stats [-
nw]
input=
name
output=
name [
method=
string] [--
overwrite]
[--
verbose] [--
quiet]
Flags:¶
- -n
-
Propagate NULLs
- -w
-
Weight according to area (slower)
- --overwrite
-
Allow output files to overwrite existing files
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- input=name
-
Name of input raster map
- output=name
-
Name for output raster map
- method=string
-
Aggregation method
Options:
average,median,mode,minimum,maximum,quart1,quart3,perc90,sum,variance,stddev
Default: average
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 rast=el_D782_6m -p
g.region res=20 -ap
r.resamp.stats input=el_D782_6m output=el_D782_20m
SEE ALSO¶
g.region,
r.resample,
r.resamp.rst r.resamp.interp
AUTHOR¶
Glynn Clements
Last changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $
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