---
name: "r.li.edgedensity"
section: "1grass"
platform: "linux"
package: "grass-doc"
version: "8.4.1-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/r.li.edgedensity"
---

# r.li.edgedensity(1grass)

Calculates edge density index on a raster map, using a 4 neighbour algorithm

## NAME

**r.li.edgedensity**  - Calculates edge density index on a raster map, using a 4 neighbour algorithm

## KEYWORDS

raster, landscape structure analysis, patch index

## SYNOPSIS

**r.li.edgedensity**\
 **r.li.edgedensity --help**\
 **r.li.edgedensity** \[-**b**\] **input**=*name* **config**=*name* **output**=*name*  \[**patch\_type**=*string*\]   \[--**overwrite**\]  \[--**help**\]  \[--**verbose**\]  \[--**quiet**\]  \[--**ui**\]

### Flags:

- **-b**

  Exclude border edges

- **--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

- **patch\_type**=*string*

  The value of the patch type\
   It can be integer, double or float; it will be changed in function of map type

## DESCRIPTION

*r.li.edgedensity* calculates:

- •

  the density of all edges of patch type *k* , or

- •

  the density of all edges in the sampling area if *k* is not specified,

with:

- •

  **k**: patch type

- •

  **m**: number of patch types

- •

  **n**: number of edge segments of patch type k

- •

  **eik** :total edge length in the landscape involving patch type k

- •

  **Area**: total landscape area

The unit is meters per hectare.

## 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.edgedensity* consider to have 0 patches.\
 If area is 0 *r.li.edgedensity* returns NULL; this is only possible if input raster is masked.

## EXAMPLES

To calculate the edge density 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.edgedensity input=my_map conf=my_conf output=my_out
```

To calculate edge density index of patch\_type 34, using "my\_conf" configuration file and on map "my\_map", saving results in "my\_out" file run:\
\

```
r.li.edgedensity input=my_map conf=my_conf output=my_out patch_type=34
```

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.edgedensity input=forests conf=movwindow7 out=forests_edgedens_mov7
r.univar forests_edgedens_mov7
```

Forest map (North Carolina sample dataset) example:\

```
g.region raster=landclass96 -p
r.mapcalc "forests = if(landclass96 == 5, 1, null() )"
r.li.edgedensity input=forests conf=movwindow7 out=forests_edgedensity_mov7
# verify
r.univar forests_edgedensity_mov7
r.to.vect input=forests output=forests type=area
d.mon wx0
d.rast forests_edgedensity_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.edgedensity source code (history)

Accessed: Monday Feb 24 17:50:42 2025

Main index \| Raster index \| Topics index \| Keywords index \| Graphical index \| Full index

© 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual