v.centroids.1grass man page

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=string] [cat=integer] [step=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags

--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog

Parameters

input=name [required]
Name of input vector map
Or data source for direct OGR access
output=name [required]
Name for output vector map
option=string
Action to be taken
Options: add
Default: add
layer=string
Layer number or name
Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
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 13:24:20 -0800 (Tue, 08 Nov 2011) $

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© 2003-2016 GRASS Development Team, GRASS GIS 7.0.4 Reference Manual

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GRASS 7.0.4 Grass User's Manual