r.spreadpath(1grass) GRASS GIS User's Manual r.spreadpath(1grass)
NAME
r.spreadpath - Recursively traces the least cost path backwards to
cells from which the cumulative cost was determined.
KEYWORDS
raster, fire, cumulative costs
SYNOPSIS
r.spreadpath
r.spreadpath --help
r.spreadpath x_input=name y_input=name [coordi-
nates=east,north[,east,north,...]] 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:
x_input=name [required]
Name of raster map containing back-path easting information
y_input=name [required]
Name of raster map containing back-path northing information
coordinates=east,north[,east,north,...]
The map E and N grid coordinates of starting points
output=name [required]
Name for output raster map
DESCRIPTION
r.spreadpath is part of the wildfire simulation toolset. Preparational
steps for the fire simulation are the calculation of the rate of spread
(ROS) with r.ros, and the creating of spread map with r.spread. Even-
tually, the fire path(s) based on starting point(s) are calculated with
r.spreadpath.
r.spreadpath recursively traces the least cost path backwards to the
origin, given backlink information input map layers and target loca-
tions from where paths are to be traced. The backlink information map
layers record each cell’s backlink UTM northing (the y_input) and east-
ing (the x_input) coordinates from which the cell’s cumulative cost was
determined.
The backlink inputs can be generated from another GRASS raster program
r.spread. One of the major applications of r.spreadpath along with
r.spread is to accurately find the least cost corridors and/or paths on
a raster setting. More information on r.spread and r.spreadpath can be
found in Xu (1994).
Parameters:
x_input=name
Name of input raster map layer containing backlink UTM easting co-
ordinates.
y_input=name
Name of input raster map layer containing backlink UTM northing co-
ordinates.
coordinates =x,y[,x,y,x,y, ...]
Each x,y coordinate pair gives the easting and northing (respec-
tively) geographic coordinates of a target point from which to
backwards trace the least cost path. As many points as desired can
be entered by the user.
output=name
Name of raster map layer to contain output. Also can be used as the
map layer of the input target points. If so used, the input target
point map will be overwritten by the output.
REFERENCES
• Xu, Jianping, 1994, Simulating the spread of wildfires using a
geographic information system and remote sensing, Ph. D. Dis-
sertation, Rutgers University, New Brunswick, New Jersey (ref).
SEE ALSO
r.spread, r.ros Sample data download: firedemo.sh (run this script
within the "Fire simulation data set" location.
AUTHOR
Jianping Xu and Richard G. Lathrop, Jr., Center for Remote Sensing and
Spatial Analysis, Rutgers University.
SOURCE CODE
Available at: r.spreadpath source code (history)
Accessed: unknown
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GRASS 7.8.7 r.spreadpath(1grass)
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