DESCRIPTION

r.li.padrange calculates the range of patch area sizes in hectares as:
r.li.padrange formula
with:

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 config and output file/map parameters. 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 folder C:\Users\userxy\.r.li\output\ (MS-Windows) or $HOME/.r.li/output/ (GNU/Linux).

If the input raster map contains only NULL values then r.li.padrange returns -1.
If you want to change these -1 values to NULL, run subsequently on the resulting map: 

r.null setnull=-1 map=my_map
after index calculation.

EXAMPLES

To calculate range of patch area 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.padrange 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.padrange map=forests conf=movwindow7 out=forests_padrange_mov7
r.univar forests_padrange_mov7

Forest map (North Carolina sample dataset) example: 

g.region rast=landclass96 -p
r.mapcalc "forests = if(landclass96 == 5, 1, null() )"
r.li.padrange map=forests conf=movwindow7 out=forests_padrange_mov7

# verify
r.univar forests_padrange_mov7
r.to.vect input=forests output=forests feature=area
d.mon x0
d.rast forests_padrange_mov7
d.vect forests type=boundary

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)
Markus Metz (statistics)

Last changed: $Date$