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]     [--verbose]
17       [--quiet]
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19   Flags:
20       -v
21           Run verbosly
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23       --overwrite
24           Allow output files to overwrite existing files
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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   Parameters:
33       x_input=string
34           Name of raster map containing back-path easting information
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36       y_input=string
37           Name of raster map containing back-path norhting information
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39       coordinate=x,y[,x,y,...]
40           The map E and N grid coordinates of starting points
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42       output=string
43           Name of spread path raster map
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DESCRIPTION

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

60       x_input=name
61              Name  of  input raster map layer containing backlink UTM easting
62              coordinates.
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64       y_input=name
65              Name of input raster map layer containing backlink UTM  northing
66              coordinates.
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68       coordinate=x,y[,x,y,x,y, ...]
69              Each x,y coordinate pair gives the easting and northing (respec‐
70              tively) geographic coordinates of a target point from  which  to
71              backwards  trace  the least cost path. As many points as desired
72              can be entered by the user.
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74       output=name
75              Name of raster map layer to contain output. Also can be used  as
76              the  map layer of the input target points. If so used, the input
77              target point map will be overwritten by the output.
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REFERENCES

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

88       Jianping Xu and Richard G. Lathrop, Jr., Center for Remote Sensing  and
89       Spatial Analysis, Rutgers University.
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91       Last changed: $Date: 2003-05-06 18:41:37 +0200 (Tue, 06 May 2003) $
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93       Full index
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95       © 2003-2008 GRASS Development Team
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99GRASS 6.3.0                                                    r.spreadpath(1)