trusty (1) r.spreadpath.1grass.gz

NAME

       r.spreadpath   - Recursively traces the least cost path backwards to cells from which the cumulative cost
       was determined.

KEYWORDS

       raster, fire

SYNOPSIS

       r.spreadpath
       r.spreadpath help
       r.spreadpath [-v] x_input=string y_input=string  [coordinate=x,y[,x,y,...]]  output=string  [--overwrite]
       [--verbose]  [--quiet]

   Flags:
       -v
           Run verbosely

       --overwrite
           Allow output files to overwrite existing files

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       x_input=string
           Name of raster map containing back-path easting information

       y_input=string
           Name of raster map containing back-path northing information

       coordinate=x,y[,x,y,...]
           The map E and N grid coordinates of starting points

       output=string
           Name of spread path raster map

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.  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 coordinates.

       y_input=name
              Name of input raster map layer containing backlink UTM northing coordinates.

       coordinate=x,y[,x,y,x,y, ...]
              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.

       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.

SEE ALSO

       r.spread, r.ros

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.

       Last changed: $Date: 2003-05-06 09:41:37 -0700 (Tue, 06 May 2003) $

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