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 map=
name conf=
name
output=
name [
patch_type=
string]
[--
overwrite] [--
verbose] [--
quiet]
Flags:¶
- --overwrite
-
Allow output files to overwrite existing files
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- map=name
-
Name of input raster map
- conf=name
-
Configuration file
- output=name
-
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
NOTES¶
Do not use absolute path names for the
output map/file. If the
"moving window" method was selected in
r.li.setup, then the
output will be a raster map, otherwise an ASCII file will be generated in the
$HOME/.r.li/output/ folder.
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 -1; this is only possible if input
raster is masked. If you want to change these -1 values to NULL, run
subsequently on the resulting map:
r.null setnull=-1 map=my_map
after index calculation.
EXAMPLES¶
To calculate the edge density index on map
my_map, using
my_conf
configuration file (previously defined with
r.li.setup) and saving
results in
my_out, run:
r.li.edgedensity map=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 map=my_map conf=my_conf output=my_out patch_type=34
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.edgedensity map=forests conf=movwindow7 out=forests_edgedens_mov7
r.univar forests_edgedens_mov7
SEE ALSO¶
r.li - package overview
r.li.setup
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)
Last changed: $Date: 2014-02-19 01:26:04 +0100 (Wed, 19 Feb 2014) $
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