r.li.mpa(1)

NAME
r.li.mpa - Calculates mean pixel attribute index on a raster map

KEYWORDS
raster, landscape structure analysis, patch index

SYNOPSIS
r.li.mpa
r.li.mpa --help
r.li.mpa input=name config=name output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]

  Flags:

--overwrite
    Allow output files to overwrite existing files

--help
    Print usage summary

--verbose
    Verbose module output

--quiet
    Quiet module output

--ui
    Force launching GUI dialog

  Parameters:

input=name [required]
    Name of input raster map

config=name [required]
    Configuration file

output=name [required]
    Name for output raster map

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 config and output file/map parameters. 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 folder C:\Users\userxy\AppData\Roaming\GRASS8\r.li\output\ (MS-Windows) or $HOME/.grass8/r.li/output/ (GNU/Linux).

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

after index calculation.

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 raster=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

Forest map (North Carolina sample dataset) example:

g.region raster=landclass96 -p
r.mapcalc "forests = if(landclass96 == 5, 1, null() )"
r.li.mpa input=forests conf=movwindow7 out=forests_mpa_mov7
# verify
r.univar forests_mpa_mov7
r.to.vect input=forests output=forests type=area
d.mon wx0
d.rast forests_mpa_mov7
d.vect forests type=boundary

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

SOURCE CODE

Available at: r.li.mpa source code (history)

Accessed: Saturday May 09 12:58:05 2026

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