GNU.WIKI: The GNU/Linux Knowledge Base

#### NAME

```       v.perturb  - Random location perturbations of GRASS vector points
```

#### KEYWORDS

```       vector, geometry, statistics
```

#### SYNOPSIS

```       v.perturb
v.perturb help
v.perturb    [-q]    input=name    output=name    [distribution=string]
parameters=float[,float,...]      [minimum=float]        [seed=integer]
[--overwrite]  [--verbose]  [--quiet]

Flags:
-q
Quiet

--overwrite
Allow output files to overwrite existing files

--verbose
Verbose module output

--quiet
Quiet module output

Parameters:
input=name
Vector points to be spatially perturbed

output=name
Name for output vector map

distribution=string
Distribution of perturbation
Options: uniform,normal
Default: uniform

parameters=float[,float,...]
Parameter(s)  of distribution. If the distribution is uniform, only
one parameter, the maximum, is needed. For a  normal  distribution,
two parameters, the mean and standard deviation, are required.

minimum=float
Minimum deviation in map units
Default: 0.0

seed=integer
Seed for random number generation
Default: 0
```

#### DESCRIPTION

```       v.perturb  reads  a vector map of points and writes the same points but
perturbs the eastings and northings  by  adding  either  a  uniform  or
normal  delta  value.  Perturbation  means  that  a  variating  spatial
deviation is added to the coordinates.
```

#### NOTES

```       The uniform distribution is always centered about zero.  The associated
parameter  is  constrained  to be positive and specifies the maximum of
the distribution; the minimum is the negation  of  that  parameter.  Do
perturb  into  a  ring  around the center, the minimum parameter can be
used.

Usually, the mean (first parameter) of the normal distribution is  zero
(i.e.,  the  distribution  is centered at zero). The standard deviation
(second parameter) is naturally constrained to be positive.

Output vector points are not guaranteed  to  be  contained  within  the
current geographic region.
```

```       v.random
v.univar
```

#### AUTHOR

```       James Darrell McCauley
when he was at: Agricultural Engineering Purdue University

Random  number generators originally written in FORTRAN by Wes Peterson
and translated to C using f2c.

Last changed: \$Date: 2011-11-08 01:42:51 -0800 (Tue, 08 Nov 2011) \$

Full index

© 2003-2013 GRASS Development Team```

All copyrights belong to their respective owners. Other content (c) 2014-2018, GNU.WIKI. Please report site errors to webmaster@gnu.wiki.
Page load time: 0.130 seconds. Last modified: November 04 2018 12:49:43.