---
name: r.li.mpa
description: Calculates mean pixel attribute index on a raster map
keywords: [ raster, landscape structure analysis, patch index ]
---

# r.li.mpa

Calculates mean pixel attribute index on a raster map

=== "Command line"

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

    Example:

    ```sh
    r.li.mpa input=name config=name output=name
    ```

=== "Python (grass.tools)"

    *grass.tools.Tools.r_li_mpa*(**input**,
        **config**,
        **output**,
        **overwrite**=*None*,
        **verbose**=*None*,
        **quiet**=*None*,
        **superquiet**=*None*)

    Example:

    ```python
    tools = Tools()
    tools.r_li_mpa(input="name", config="name", output="name")
    ```

    This grass.tools API is experimental in version 8.5 and expected to be stable in version 8.6.

=== "Python (grass.script)"

    *grass.script.run_command*("***r.li.mpa***",
        **input**,
        **config**,
        **output**,
        **overwrite**=*None*,
        **verbose**=*None*,
        **quiet**=*None*,
        **superquiet**=*None*)

    Example:

    ```python
    gs.run_command("r.li.mpa", input="name", config="name", output="name")
    ```

## Parameters

=== "Command line"

    **input**=*name* **[required]**  
    &nbsp;&nbsp;&nbsp;&nbsp;Name of input raster map  
    **config**=*name* **[required]**  
    &nbsp;&nbsp;&nbsp;&nbsp;Configuration file  
    **output**=*name* **[required]**  
    &nbsp;&nbsp;&nbsp;&nbsp;Name for output raster map  
    **--overwrite**  
    &nbsp;&nbsp;&nbsp;&nbsp;Allow output files to overwrite existing files  
    **--help**  
    &nbsp;&nbsp;&nbsp;&nbsp;Print usage summary  
    **--verbose**  
    &nbsp;&nbsp;&nbsp;&nbsp;Verbose module output  
    **--quiet**  
    &nbsp;&nbsp;&nbsp;&nbsp;Quiet module output  
    **--qq**  
    &nbsp;&nbsp;&nbsp;&nbsp;Very quiet module output  
    **--ui**  
    &nbsp;&nbsp;&nbsp;&nbsp;Force launching GUI dialog

=== "Python (grass.tools)"

    **input** : str | np.ndarray, *required*  
    &nbsp;&nbsp;&nbsp;&nbsp;Name of input raster map  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, raster, *name*  
    **config** : str | io.StringIO, *required*  
    &nbsp;&nbsp;&nbsp;&nbsp;Configuration file  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, file, *name*  
    **output** : str | type(np.ndarray) | type(np.array) | type(gs.array.array), *required*  
    &nbsp;&nbsp;&nbsp;&nbsp;Name for output raster map  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: output, raster, *name*  
    **overwrite** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Allow output files to overwrite existing files  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **verbose** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Verbose module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **quiet** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Quiet module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **superquiet** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Very quiet module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  

    Returns:

    **result** : grass.tools.support.ToolResult | np.ndarray | tuple[np.ndarray] | None  
    If the tool produces text as standard output, a *ToolResult* object will be returned. Otherwise, `None` will be returned. If an array type (e.g., *np.ndarray*) is used for one of the raster outputs, the result will be an array and will have the shape corresponding to the computational region. If an array type is used for more than one raster output, the result will be a tuple of arrays.

    Raises:

    *grass.tools.ToolError*: When the tool ended with an error.

=== "Python (grass.script)"

    **input** : str, *required*  
    &nbsp;&nbsp;&nbsp;&nbsp;Name of input raster map  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, raster, *name*  
    **config** : str, *required*  
    &nbsp;&nbsp;&nbsp;&nbsp;Configuration file  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, file, *name*  
    **output** : str, *required*  
    &nbsp;&nbsp;&nbsp;&nbsp;Name for output raster map  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: output, raster, *name*  
    **overwrite** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Allow output files to overwrite existing files  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **verbose** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Verbose module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **quiet** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Quiet module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **superquiet** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Very quiet module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*

## 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:  
![rlimpa formula](rlimpa_formula.png)  
with:  

- *i*: attribute
- *m*: number of non-null attributes in the sampling area
- *w_i*: 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:

```sh
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:

```sh
r.li.mpa input=my_map conf=my_conf output=my_out
```

Forest map (Spearfish sample dataset) example:

```sh
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:

```sh
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](r.li.md) (package overview),
[g.gui.rlisetup](g.gui.rlisetup.md)*

## 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](https://doi.org/10.2737/PNW-GTR-351))

## 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](https://github.com/OSGeo/grass/tree/main/raster/r.li/r.li.mpa)
([history](https://github.com/OSGeo/grass/commits/main/raster/r.li/r.li.mpa))  
Accessed: Monday May 11 17:54:12 2026
