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v.centroids

Adds missing centroids to closed boundaries.

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

Example:

v.centroids input=name output=name

grass.script.run_command("v.centroids", input, output, option="add", layer="1", cat=1, step=1, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("v.centroids", input="name", output="name")

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

input : str, required
    Name of input vector map
    Or data source for direct OGR access
    Used as: input, vector, name
output : str, required
    Name for output vector map
    Used as: output, vector, name
option : str, optional
    Action to be taken
    Allowed values: add
    Default: add
layer : str, optional
    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.
    Used as: input, layer
    Default: 1
cat : int, optional
    Category number starting value
    Used as: input, cats
    Default: 1
step : int, optional
    Category increment
    Default: 1
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

In GRASS GIS, a centroid is a point within a closed ring of boundaries. A vector area is defined as composite entity consisting of a set of closed boundaries and a centroid. The attribute information associated with this 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.

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

v.centroids example
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)
Latest change: Wednesday Feb 12 23:02:46 2025 in commit 9c11460