DESCRIPTION
r.li.mpa (mean pixel attribute) calculates the average value of the
attribute of all the non-null cells in the sampling area as:
with:
- i: attribute
- m: number of non-null attributes in the sampling area
- wi: number of cells of attribute i
- size: size of sampling area (in cells)
NOTES
Do not use absolute path names for the output map/file.
If the "moving window" method was selected in g.gui.rlisetup, then the
output will be a raster map, otherwise an ASCII file will be generated in
the $HOME/.grass7/r.li/output/ folder.
If the input raster map contains only NULL values then r.li.mpa considers to
have 0 patches.
If area is 0 r.li.mpa returns -1; it is possible only if the
raster is masked
If you want to change these -1 values to NULL, run subsequently on the resulting map:
r.null setnull=-1 input=my_map
EXAMPLES
To calculate the mean pixel attribute index on map my_map, using
my_conf configuration file (previously defined with
g.gui.rlisetup) and saving results in my_out, run:
r.li.mpa input=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.mpa input=forests conf=movwindow7 out=forests_mpa_mov7
r.univar forests_mpa_mov7
SEE ALSO
r.li - package overview
g.gui.rlisetup
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
Last changed: $Date$