.TH r.spreadpath 1grass "" "GRASS 6.4.4" "Grass 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
.SH SYNOPSIS
\fBr.spreadpath\fR
.br
\fBr.spreadpath help\fR
.br
\fBr.spreadpath\fR [\-\fBv\fR] \fBx_input\fR=\fIstring\fR \fBy_input\fR=\fIstring\fR  [\fBcoordinate\fR=\fIx,y\fR[,\fIx,y\fR,...]]  \fBoutput\fR=\fIstring\fR  [\-\-\fBoverwrite\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR] 
.SS Flags:
.IP "\fB\-v\fR" 4m
.br
Run verbosely
.IP "\fB\-\-overwrite\fR" 4m
.br
Allow output files to overwrite existing files
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.PP
.SS Parameters:
.IP "\fBx_input\fR=\fIstring\fR" 4m
.br
Name of raster map containing back-path easting information
.IP "\fBy_input\fR=\fIstring\fR" 4m
.br
Name of raster map containing back-path northing information
.IP "\fBcoordinate\fR=\fIx,y[,\fIx,y\fR,...]\fR" 4m
.br
The map E and N grid coordinates of starting points
.IP "\fBoutput\fR=\fIstring\fR" 4m
.br
Name of spread path raster map
.PP
.SH DESCRIPTION
\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's backlink UTM northing (the y_input) and easting (the
x_input) coordinates from which the cell's 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
.br
Name of input raster map layer containing backlink UTM easting
coordinates.
.IP "\fBy_input=\fR\fIname\fR
.br
Name of input raster map layer containing backlink UTM northing coordinates.
.IP "\fBcoordinate=\fR\fIx,y[,x,y,x,y, ...]\fR
.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
.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.
.PP
.SH SEE ALSO
\fIr.spread\fR,
\fIr.ros\fR
.SH REFERENCES
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.
.SH AUTHOR
Jianping Xu and Richard G. Lathrop, Jr., Center for Remote Sensing and
Spatial Analysis, Rutgers University.
.PP
\fILast changed: $Date: 2003-05-06 18:41:37 +0200 (Tue, 06 May 2003) $\fR
.PP
Full index
.PP
© 2003-2014 GRASS Development Team