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NAME
r.clump - Recategorizes data in a raster map by grouping cells that form physically discrete areas into unique categories.
KEYWORDS
raster, statistics, reclass
SYNOPSIS
r.clump
r.clump help
r.clump [-q] input=name output=name [title="string"] [--overwrite] [--verbose] [--quiet]
Flags:
- -q
- Run quietly
- --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
- title="string"
- Title for output raster map
DESCRIPTION
r.clump finds all areas of contiguous cell category values in
the input raster map. It assigns a unique category value to each such
area ("clump") in the resulting output raster map.
Category distinctions in the input raster map are preserved. This
means that if distinct category values are adjacent, they will NOT be
clumped together. The user can
run r.reclass prior
to r.clump to recategorize cells and reassign cell category
values.
NOTES
r.clump moves a 2x2 matrix over the input raster map. The
lower right-hand corner of the matrix is grouped with the cells above
it, or to the left of it (diagonal cells are not considered.)
r.clump works properly with raster map that contain only
"fat" areas (more than a single cell in width). Linear
elements (lines that are a single cell wide) may or may not be clumped
together depending on the direction of the line - horizontal and
vertical lines of cells are considered to be contiguous, but diagonal
lines of cells are not considered to be contiguous and are broken up
into separate clumps.
A random color table and other support files are generated for the
output raster map.
EXAMPLES
Perform clumping on "lakes" map (North Carolina sample dataset) and
report area sizes for each lake individually rather by waterbody type:
g.region rast=lakes -p
# report sizes by waterbody type
r.report lakes units=h
# clump per raster polygon
r.clump lakes out=lakes_individual
# report sizes by individual waterbody
r.report lakes_individual units=h
SEE ALSO
r.average,
r.buffer,
r.distance,
r.grow,
r.mapcalc,
r.mfilter,
r.neighbors,
r.to.vect,
r.reclass,
r.statistics,
r.support
AUTHOR
Michael Shapiro, U.S. Army Construction Engineering Research
Laboratory
Last changed: $Date: 2014-08-19 09:27:27 -0700 (Tue, 19 Aug 2014) $
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