.TH r.li.patchdensity 1grass "" "GRASS 6.4.2" "Grass User's Manual"
.SH NAME
\fI\fBr.li.patchdensity\fR\fR  - Calculates patch density index on a raster map, using a 4 neighbour algorithm
.SH KEYWORDS
raster, landscape structure analysis, patch index
.SH SYNOPSIS
\fBr.li.patchdensity\fR
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\fBr.li.patchdensity help\fR
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\fBr.li.patchdensity map\fR=\fIname\fR \fBconf\fR=\fIstring\fR \fBoutput\fR=\fIname\fR  [--\fBoverwrite\fR]  [--\fBverbose\fR]  [--\fBquiet\fR] 
.SS Flags:
.IP "\fB--overwrite\fR" 4m
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Allow output files to overwrite existing files
.IP "\fB--verbose\fR" 4m
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Verbose module output
.IP "\fB--quiet\fR" 4m
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Quiet module output
.PP
.SS Parameters:
.IP "\fBmap\fR=\fIname\fR" 4m
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Name of input raster map
.IP "\fBconf\fR=\fIstring\fR" 4m
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Configuration file
.IP "\fBoutput\fR=\fIname\fR" 4m
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Name for output raster map
.PP
.SH DESCRIPTION
\fIr.li.patchdensity\fR is a patch index for \fIr.li\fR suite.
It calculates the function:
\fC
.DS
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f(sample_area) = (Patch_Number/Area) * 1000000
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.DE
\fR
that is 1000000 by number of patch for area unit.
This index is calculated using a 4 neighbour algorithm.
.SH EXAMPLES
To calculate patch density index on map \fImy_map\fR, using \fImy_conf\fR
configuration file (previously defined with \fIr.li.setup\fR) and saving
results in the raster map \fImy_out\fR, run:
\fC
.DS
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r.li.patchdensity map=my_map conf=my_conf out=my_out
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.DE
\fR
.PP
Example for Spearfish forest areas:
\fC
.DS
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g.region rast=landcover.30m -p
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# extract forested areas:
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r.category landcover.30m
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r.mapcalc "forests=if(landcover.30m >= 41 && landcover.30m <=43,1,null())"
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# patch density (7x7 moving window defined in r.li.setup):
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r.li.patchdensity forests conf=movwindow7 out=forests_p_dens7
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d.rast.leg forests_p_dens7
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r.to.vect forests out=forests feature=area
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d.vect forests type=boundary
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.DE
\fR
.SH NOTES
A map of NULL values is considered to have zero patches. 
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If you want to have null values instead run 
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\fC
.DS
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r.null setnull=0 map=my_out
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\fC
.DS
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after index calculation.
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If raster area is 0, \fIr.li.patchdensity\fR returns -1. This is only possible
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if the raster is masked.
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.SH SEE ALSO
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\fIr.li\fR package overview 
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\fIr.li.daemon\fR
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\fIr.li.setup\fR
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.SH AUTHORS
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Claudio Porta and Lucio Davide Spano, students of Computer Science 
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University of Pisa (Italy).
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Commission from Faunalia Pontedera (PI) (www.faunalia.it)
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\fC
.DS
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.PP
Full index
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.PP
© 2003-2011 GRASS Development Team
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