r.spreadpath <main>   GRASS Reference Manual  <main> r.spreadpath



NAME
     r.spreadpath - Recursively traces the least cost path
     backwards to cells from which the cumulative cost was
     determined. (GRASS Raster Program)

SYNOPSIS
     r.spreadpath

     r.spreadpath help

     r.spreadpath [-v] x_input=name

DESCRIPTION
     r.spreadpath 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.

     The backlink inputs can be generated from another GRASS
     raster program r.spread can be found in Xu (1994).

Flags:
     Run verbosely.

Parameters:
     Name of input raster map layer containing backlink UTM
     easting coordinates.  Name of input raster map layer
     containing backlink UTM northing coordinates.  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.  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.

OPTIONS
     The user can run r.spreadpath without specifying flag
     setting and parameter values on the command line. In this
     case, the user will be prompted for input.

     Alternately, the user can run r.spreadpath non-
     interactively, by specifying the names of raster map layers
     and desired options on the command line, using the form:

     r.spreadpath [-v] x_input=name

SEE ALSO
     r.ros.



GRASS 5.0beta6	      GRASS Development Team			1






r.spreadpath <main>   GRASS Reference Manual  <main> r.spreadpath



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.

AUTHOR
     Jianping Xu and Richard G. Lathrop, Jr., Center for Remote
     Sensing and Spatial Analysis, Rutgers University.

NOTICE
     This program is part of the alpha section of the GRASS
     distribution. Unlike the code in the main section of GRASS,
     the alpha code has not yet been fully tested for one release
     cycle.









































2		      GRASS Development Team	   GRASS 5.0beta6