GRASS logo

NAME - Calculates mean patch size index on a raster map, using a 4 neighbour algorithm


raster, landscape structure analysis, patch index

SYNOPSIS --help input=name config=name output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]


Allow output files to overwrite existing files
Print usage summary
Verbose module output
Quiet module output
Force launching GUI dialog


input=name [required]
Name of input raster map
config=name [required]
Configuration file
output=name [required]
Name for output raster map

Table of contents

DESCRIPTION (mean patch size) calculates the mean size of the patches in the sampling area as:
MPS = A / Npatch
with: The unit of the mean size is hectare.

This index is calculated using a 4 neighbour algorithm, diagonal cells are ignored when tracing a patch.


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\GRASS7\\output\ (MS-Windows) or $HOME/.grass7/ (GNU/Linux).

If the sample area contains only NULL value cells, returns 0 (zero).


To calculate mean path size index on map my_map, using my_conf configuration file (previously defined with g.gui.rlisetup) and saving results in my_out, run: 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())" input=forests conf=movwindow7 out=forests_mps_mov7
r.univar forests_mps_mov7

Forest map (North Carolina sample dataset) example:

g.region raster=landclass96 -p
r.mapcalc "forests = if(landclass96 == 5, 1, null() )" input=forests conf=movwindow7 out=forests_mps_mov7

# verify
r.univar forests_mps_mov7 input=forests output=forests type=area
d.mon wx0
d.rast forests_mps_mov7
d.vect forests type=boundary

SEE ALSO - package overview


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)


Michael Shapiro - CERL (patch identification)
Markus Metz (statistics)

Last changed: $Date: 2014-12-19 13:17:36 -0800 (Fri, 19 Dec 2014) $


Available at: source code (history)

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

© 2003-2018 GRASS Development Team, GRASS GIS 7.5.svn Reference Manual