Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.
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 access this is the layer name.
- 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.
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
v.category
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: Thursday Feb 03 11:10:06 2022 in commit: 547ff44e6aecfb4c9cbf6a4717fc14e521bec0be
Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.
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© 2003-2023
GRASS Development Team,
GRASS GIS 8.2.2dev Reference Manual