v.centroids (1grass)

vector, centroid, area

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

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.

v.category

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 (Tue, 08 Nov 2011) $

Full index

� 2003-2014 GRASS Development Team