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