1v.perturb(1)                  Grass User's Manual                 v.perturb(1)
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NAME

6       v.perturb  - Random location perturbations of GRASS vector points
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KEYWORDS

9       vector
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SYNOPSIS

12       v.perturb
13       v.perturb help
14       v.perturb  [-q]  input=name output=name  [distribution=string]  parame‐
15       ters=float[,float,...]   [minimum=float]    [seed=integer]     [--over‐
16       write]
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18   Flags:
19       -q  Quiet
20
21       --overwrite
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23   Parameters:
24       input=name
25           Vector points to be spatially perturbed
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27       output=name
28           Name for output vector map
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30       distribution=string
31           Distribution  of perturbation Options: uniform,normal Default: uni‐
32           form
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34       parameters=float[,float,...]
35           Parameter(s) of distribution. If the distribution is uniform,  only
36           one  parameter,  the maximum, is needed. For a normal distribution,
37           two parameters, the mean and standard deviation, are required.
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39       minimum=float
40           Minimum deviation in map units Default: 0.0
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42       seed=integer
43           Seed for random number generation Default: 0
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DESCRIPTION

46       v.perturb reads a vector map of points and writes the same  points  but
47       perturbs  the eastings and northings by adding either a uniform or nor‐
48       mal delta value. Perturbation means that a variating spatial  deviation
49       is added to the coordinates.
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NOTES

52       The uniform distribution is always centered about zero.  The associated
53       parameter is constrained to be positive and specifies  the  maximum  of
54       the  distribution;  the  minimum  is the negation of that parameter. Do
55       perturb into a ring around the center, the  minimum  parameter  can  be
56       used.
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58       Usually,  the mean (first parameter) of the normal distribution is zero
59       (i.e., the distribution is centered at zero).  The  standard  deviation
60       (second parameter) is naturally constrained to be positive.
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62       Output vector points are not guaranteed to be contained within the cur‐
63       rent geographic region.
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SEE ALSO

66       v.random
67       v.univar
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AUTHOR

70       James Darrell McCauley
71       when he was at: Agricultural Engineering Purdue University
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73       Random number generators originally written in FORTRAN by Wes  Peterson
74       and translated to C using f2c.
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76       Last changed: $Date: 2006/03/03 10:41:45 $
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78       Full index
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82GRASS 6.2.2                                                       v.perturb(1)