.TH r.spreadpath 1grass "" "GRASS 8.3.2" "GRASS GIS User's Manual"
.SH NAME
\fI\fBr.spreadpath\fR\fR  \- Recursively traces the least cost path backwards to cells from which the cumulative cost was determined.
.SH KEYWORDS
raster, fire, cumulative costs
.SH SYNOPSIS
\fBr.spreadpath\fR
.br
\fBr.spreadpath \-\-help\fR
.br
\fBr.spreadpath\fR \fBx_input\fR=\fIname\fR \fBy_input\fR=\fIname\fR  [\fBcoordinates\fR=\fIeast,north\fR[,\fIeast,north\fR,...]]  \fBoutput\fR=\fIname\fR  [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-\-overwrite\fR" 4m
.br
Allow output files to overwrite existing files
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBx_input\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of raster map containing back\-path easting information
.IP "\fBy_input\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of raster map containing back\-path northing information
.IP "\fBcoordinates\fR=\fIeast,north[,\fIeast,north\fR,...]\fR" 4m
.br
The map E and N grid coordinates of starting points
.IP "\fBoutput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name for output raster map
.SH DESCRIPTION
\fIr.spreadpath\fR is part of the wildfire simulation toolset. Preparational
steps for the fire simulation are the calculation of the rate of spread (ROS)
with \fIr.ros\fR, and the creating of spread map with \fIr.spread\fR.
Eventually, the fire path(s) based on starting point(s) are calculated
with \fIr.spreadpath\fR.
.PP
\fIr.spreadpath\fR recursively traces the least cost path backwards to
the origin, given backlink information input map layers and target locations
from where paths are to be traced. The backlink information map layers
record each cell\(cqs backlink UTM northing (the y_input) and easting (the
x_input) coordinates from which the cell\(cqs cumulative cost was determined.
.PP
The backlink inputs can be generated from another GRASS raster program
\fIr.spread\fR. One of the major applications of \fIr.spreadpath\fR
along with \fIr.spread\fR is to accurately find the least cost corridors
and/or paths on a raster setting. More information on \fIr.spread\fR and
\fIr.spreadpath\fR can be found in Xu (1994).
.SH Parameters:
.IP "\fBx_input=\fR\fIname\fR " 4m
.br
Name of input raster map layer containing backlink UTM easting
coordinates.
.IP "\fBy_input=\fR\fIname\fR " 4m
.br
Name of input raster map layer containing backlink UTM northing coordinates.
.IP "\fBcoordinates =\fR\fIx,y[,x,y,x,y, ...]\fR " 4m
.br
Each x,y coordinate pair gives the easting and northing
(respectively) 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.
.IP "\fBoutput=\fR\fIname\fR " 4m
.br
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.
.SH REFERENCES
.RS 4n
.IP \(bu 4n
Xu, Jianping, 1994, Simulating the spread of wildfires using a
geographic information system and remote sensing, Ph. D. Dissertation,
Rutgers University, New Brunswick, New Jersey
(ref).
.RE
.SH SEE ALSO
\fI
r.spread,
r.ros
\fR
Sample data download: firedemo.sh
(run this script within the \(dqFire simulation data set\(dq location).
.SH AUTHORS
Jianping Xu and Richard G. Lathrop, Jr., Center for Remote Sensing and
Spatial Analysis, Rutgers University.
.SH SOURCE CODE
.PP
Available at:
r.spreadpath source code
(history)
.PP
Accessed: Friday Mar 08 07:34:42 2024
.PP
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.PP
© 2003\-2024
GRASS Development Team,
GRASS GIS 8.3.2 Reference Manual