## NAME

v.centroids - Adds missing centroids to closed boundaries.

## KEYWORDS

vector, centroid, area

## SYNOPSIS

v.centroids
v.centroids help
v.centroids input=name output=name [option=string] [layer=integer] [cat=integer] [step=integer] [--overwrite] [--verbose] [--quiet]

### Flags:

--overwrite
  Allow output files to overwrite existing files
--verbose
  Verbose module output
--quiet
  Quiet module output

### Parameters:

input=name
  Name of input vector map
output=name
  Name for output vector map
option=string
  Action to be taken
  Options: add
  Default: add
layer=integer
  Layer number
  Default: 1
cat=integer
  Category number starting value
  Default: 1
step=integer
  Category increment
  Default: 1

## DESCRIPTION

GRASS defines vector areas as composite entities consisting of a set of closed boundaries and a centroid. The attribute information associated with that area is linked to the centroid. The v.centroids module adds centroids to closed boundaries in the input file and assigns a category number to them. The starting value as well as the increment size may be set using optional parameters.

Multiple attributes may be linked to a single vector entity through numbered fields referred to as layers. Refer to v.category for more details, as v.centroids is simply a frontend to that module.

The boundary itself is often stored without any category reference as it can mark the border between two adjacent areas. Thus it would be ambiguous as to which feature the attribute would belong. In some cases it may, for example, represent a road between two parcels of land. In this case it is entirely appropriate for the boundary to contain category information.

## SEE ALSO

v.category

## AUTHORS

module: M. Hamish Bowman, Dept. Marine Science, Otago University, New Zealand
help page: Trevor Wiens

Last changed: $Date: 2011-11-08 10:42:51 +0100 (út, 08 XI 2011) $

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