1r.clump(1)                    Grass User's Manual                   r.clump(1)
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NAME

6       r.clump   -  Recategorizes data in a raster map layer by grouping cells
7       that form physically discrete areas into unique categories.
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KEYWORDS

10       raster
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SYNOPSIS

13       r.clump
14       r.clump help
15       r.clump [-q] input=name output=name  [title="string"]   [--overwrite]
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17   Flags:
18       -q  Quiet
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20       --overwrite
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22   Parameters:
23       input=name
24           Name of input raster map
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26       output=name
27           Name for output raster map
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29       title=
30           Title, in quotes
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DESCRIPTION

33       r.clump finds all areas of contiguous cell category values in the input
34       raster  map layer name. It assigns a unique category value to each such
35       area ("clump") in the resulting output raster map layer  name.  If  the
36       user  does  not provide input and output map layer names on the command
37       line, the program will prompt the user for these names, using the stan‐
38       dard parser interface (see manual entry for parser).  Category distinc‐
39       tions in the input raster map layer are preserved.  This means that  if
40       distinct  category  values  are  adjacent,  they  will  NOT  be clumped
41       together.  (The user can run <A  HREF="r.reclass.html">r.reclass  prior
42       to r.clump to recategorize cells and reassign cell category values.)
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ALGORITHM

45       r.clump  moves a 2x2 matrix over the input raster map layer.  The lower
46       right-hand corner of the matrix is grouped with the cells above it,  or
47       to the left of it.  (Diagonal cells are not considered.)
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NOTES

50       r.clump  works  properly with raster map layers that contain only "fat"
51       areas (more than a single cell in width).  Linear elements (lines  that
52       are a single cell wide) may or may not be clumped together depending on
53       the direction of the line -- horizontal and vertical lines of cells are
54       considered  to  be contiguous, but diagonal lines of cells are not con‐
55       sidered to be contiguous and are broken up into separate clumps.
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57       A random color table and other support files are generated for the out‐
58       put raster map layer.
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SEE ALSO

61       r.average
62       r.buffer
63       r.grow
64        r.mapcalc
65       r.mfilter
66       r.neighbors
67       r.to.vect
68       r.reclass
69       r.support
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AUTHOR

72       Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
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74       Last changed: $Date: 2006/04/18 15:14:26 $
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76       Full index
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80GRASS 6.2.2                                                         r.clump(1)
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