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, fire, cumulative costs
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SYNOPSIS

13       r.spreadpath
14       r.spreadpath --help
15       r.spreadpath        x_input=name         y_input=name          [coordi‐
16       nates=east,north[,east,north,...]]       output=name      [--overwrite]
17       [--help]  [--verbose]  [--quiet]  [--ui]
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19   Flags:
20       --overwrite
21           Allow output files to overwrite existing files
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23       --help
24           Print usage summary
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26       --verbose
27           Verbose module output
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29       --quiet
30           Quiet module output
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32       --ui
33           Force launching GUI dialog
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35   Parameters:
36       x_input=name [required]
37           Name of raster map containing back-path easting information
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39       y_input=name [required]
40           Name of raster map containing back-path northing information
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42       coordinates=east,north[,east,north,...]
43           The map E and N grid coordinates of starting points
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45       output=name [required]
46           Name for output raster map
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DESCRIPTION

49       r.spreadpath is part of the wildfire simulation toolset.  Preparational
50       steps for the fire simulation are the calculation of the rate of spread
51       (ROS) with r.ros, and the creating of spread map with r.spread.   Even‐
52       tually, the fire path(s) based on starting point(s) are calculated with
53       r.spreadpath.
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55       r.spreadpath recursively traces the least cost path  backwards  to  the
56       origin,  given  backlink  information input map layers and target loca‐
57       tions from where paths are to be traced. The backlink  information  map
58       layers record each cell’s backlink UTM northing (the y_input) and east‐
59       ing (the x_input) coordinates from which the cell’s cumulative cost was
60       determined.
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62       The  backlink inputs can be generated from another GRASS raster program
63       r.spread. One of the major  applications  of  r.spreadpath  along  with
64       r.spread is to accurately find the least cost corridors and/or paths on
65       a raster setting. More information on r.spread and r.spreadpath can  be
66       found in Xu (1994).
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Parameters:

69       x_input=name
70           Name  of  input  raster  map  layer containing backlink UTM easting
71           coordinates.
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73       y_input=name
74           Name of input raster map layer  containing  backlink  UTM  northing
75           coordinates.
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77       coordinates =x,y[,x,y,x,y, ...]
78           Each  x,y  coordinate  pair gives the easting and northing (respec‐
79           tively) geographic coordinates of a  target  point  from  which  to
80           backwards  trace the least cost path. As many points as desired can
81           be entered by the user.
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83       output=name
84           Name of raster map layer to contain output. Also can be used as the
85           map  layer of the input target points. If so used, the input target
86           point map will be overwritten by the output.
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REFERENCES

89           ·   Xu, Jianping, 1994, Simulating the spread of wildfires using  a
90               geographic  information  system and remote sensing, Ph. D. Dis‐
91               sertation, Rutgers University, New Brunswick, New Jersey (ref).
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SEE ALSO

94        r.spread, r.ros Sample data download:  firedemo.sh  (run  this  script
95       within the "Fire simulation data set" location.
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AUTHOR

98       Jianping  Xu and Richard G. Lathrop, Jr., Center for Remote Sensing and
99       Spatial Analysis, Rutgers University.
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SOURCE CODE

102       Available at: r.spreadpath source code (history)
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104       Main index | Raster index | Topics index | Keywords index  |  Graphical
105       index | Full index
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107       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual
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111GRASS 7.8.2                                                    r.spreadpath(1)