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r.li.mps(1grass) Grass User's Manual r.li.mps(1grass)

NAME

r.li.mps - Calculates mean patch size index on a raster map, using a 4 neighbour algorithm

KEYWORDS

raster, landscape structure analysis, patch index

SYNOPSIS

r.li.mps
 
r.li.mps help
 
r.li.mps map=name conf=name 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=name
 
Configuration file
output=name
 
Name for output raster map

DESCRIPTION

r.li.mps (mean patch size) calculates the mean size of the patches in the sampling area as:
 
 
MPS = A / Npatch
 
with:
A:sampling area size without null cells
Npatch: number of patches
The unit of the mean size is hectare.
This index is calculated using a 4 neighbour algorithm, diagonal cells are ignored when tracing a patch.

NOTES

Do not use absolute path names for the output map/file. If the "moving window" method was selected in r.li.setup, then the output will be a raster map, otherwise an ASCII file will be generated in the $HOME/.r.li/output/ folder.
If the input raster contains NULL value cells, r.li.mps returns 0 for these cells.
 
If you want to change these 0 values to NULL, run subsequently on the resulting map:
 
r.null setnull=0 map=my_map
 
after index calculation.

EXAMPLES

To calculate mean path size index on map my_map, using my_conf configuration file (previously defined with r.li.setup) and saving results in my_out, run:
 
r.li.mps map=my_map conf=my_conf output=my_out
 
Forest map (Spearfish sample dataset) example:
 
g.region rast=landcover.30m -p
 
r.mapcalc "forests = if(landcover.30m >= 41 && landcover.30m <= 43,1,null())"
 
r.li.mps map=forests conf=movwindow7 out=forests_mps_mov7
 
r.univar forests_mps_mov7
 

SEE ALSO

r.li - package overview
 
r.li.setup

REFERENCES

McGarigal, K., and B. J. Marks. 1995. FRAGSTATS: spatial pattern analysis program for quantifying landscape structure. USDA For. Serv. Gen. Tech. Rep. PNW-351. (PDF)

AUTHORS

Serena Pallecchi student of Computer Science University of Pisa (Italy).
 
Commission from Faunalia Pontedera (PI), Italy (www.faunalia.it)
Last changed: $Date: 2014-02-19 01:26:04 +0100 (Wed, 19 Feb 2014) $
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