Provided by: grass-doc_6.4.3-3_all
v.perturb - Random location perturbations of GRASS vector points
vector, geometry, statistics
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
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.
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.
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