r.spreadpath(1)

1r.spreadpath(1)               Grass User's Manual              r.spreadpath(1)
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NAME

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

10       raster
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SYNOPSIS

13       r.spreadpath
14       r.spreadpath help
15       r.spreadpath    [-v]    x_input=string     y_input=string      [coordi‐
16       nate=x,y[,x,y,...]]  output=string  [--overwrite]
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18   Flags:
19       -v  Run verbosly
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21       --overwrite
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23   Parameters:
24       x_input=string
25           Name of raster map containing back-path easting information
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27       y_input=string
28           Name of raster map containing back-path norhting information
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30       coordinate=x,y[,x,y,...]
31           The map E and N grid coordinates of starting points
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33       output=string
34           Name of spread path raster map
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DESCRIPTION

37       r.spreadpath  recursively  traces  the least cost path backwards to the
38       origin, given backlink information input map layers  and  target  loca‐
39       tions  from  where paths are to be traced. The backlink information map
40       layers record each cell's backlink UTM northing (the y_input) and east‐
41       ing (the x_input) coordinates from which the cell's cumulative cost was
42       determined.
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44       The backlink inputs can be generated from another GRASS raster  program
45       r.spread.  One  of  the  major  applications of r.spreadpath along with
46       r.spread is to accurately find the least cost corridors and/or paths on
47       a  raster setting. More information on r.spread and r.spreadpath can be
48       found in Xu (1994).
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Parameters:

51       x_input=name
52              Name of input raster map layer containing backlink  UTM  easting
53              coordinates.
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55       y_input=name
56              Name  of input raster map layer containing backlink UTM northing
57              coordinates.
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59       coordinate=x,y[,x,y,x,y, ...]
60              Each x,y coordinate pair gives the easting and northing (respec‐
61              tively)  geographic  coordinates of a target point from which to
62              backwards trace the least cost path. As many points  as  desired
63              can be entered by the user.
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65       output=name
66              Name  of raster map layer to contain output. Also can be used as
67              the map layer of the input target points. If so used, the  input
68              target point map will be overwritten by the output.
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REFERENCES

74       Xu,  Jianping,  1994,  Simulating  the spread of wildfires using a geo‐
75       graphic information system and remote  sensing,  Ph.  D.  Dissertation,
76       Rutgers University, New Brunswick, New Jersey.
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AUTHOR

79       Jianping  Xu and Richard G. Lathrop, Jr., Center for Remote Sensing and
80       Spatial Analysis, Rutgers University.
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82       Last changed: $Date: 2003/05/06 16:41:37 $
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84       Full index
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88GRASS 6.2.2                                                    r.spreadpath(1)