v.centroids(1grass) GRASS GIS User's Manual v.centroids(1grass)
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=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 ac-
cess 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 de-
tails, 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 am-
biguous 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 cate-
gory information.
EXAMPLES
Create an area from a closed line using North Carolina sample dataset:
v.type input=busroute11 output=busroute11_boundary from_type=line to_type=boundary
v.centroids input=busroute11_boundary output=busroute11_area
Figure: Creating area from closed line
SEE ALSO
v.category
AUTHORS
module: M. Hamish Bowman, Dept. Marine Science, Otago University, New
Zealand
help page: Trevor Wiens
SOURCE CODE
Available at: v.centroids source code (history)
Accessed: unknown
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GRASS 7.8.7 v.centroids(1grass)
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