NAME¶

v.voronoi - Creates a Voronoi diagram from an input vector map containing points or centroids.

KEYWORDS¶

vector, geometry, triangulation

SYNOPSIS¶

v.voronoi v.voronoi help v.voronoi [-lt] input=name output=name [-- overwrite] [--verbose] [--quiet]

Flags:¶

-l

 

Output tessellation as a graph (lines), not areas

-t

 

Do not create attribute table

--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

DESCRIPTION¶

v.voronoi uses an existing vector points map (input) to create a Voronoi diagram (Thiessen polygons) in a new vector map ( output). The bounds of the output map are limited by the current region. (see g.region) Voronoi diagram and Delaunay triangulation example: | Delaunay Triangulation (left pane), Voronoi diagram (center pane), and both (right pane)

NOTES¶

Voronoi diagrams may be used for nearest-neighbor flood filling. Give the centroids attributes (start with v.db.addcol), then optionally convert to a raster map with v.to.rast.

EXAMPLE¶

Commands used with the Spearfish dataset to create the above figure.
g.region n=4927250 s=4919400 w=588650 e=594850
d.frame -c fr=one at=0,100,0,33.3333
d.frame -c fr=two at=0,100,33.3333,66.6667
d.frame -c fr=three at=0,100,66.6667,100
v.delaunay -lr in=archsites out=arch_delaunay
d.frame -s one
d.vect arch_delaunay
d.vect archsites color=red fcolor=red size=5 icon=basic/circle
v.voronoi -l in=archsites out=arch_voronoi
d.frame -s two
d.vect arch_voronoi type=line
d.vect archsites color=red fcolor=red size=5 icon=basic/circle
d.frame -s three
d.vect arch_voronoi type=line
d.vect arch_delaunay color=blue
d.vect archsites color=red fcolor=red size=5 icon=basic/circle

BUGS¶

Only attribute table of field 1 is copied.

REFERENCES¶

Steve J. Fortune, (1987). A Sweepline Algorithm for Voronoi Diagrams, Algorithmica 2, 153-174.

SEE ALSO¶

g.region, v.delaunay, v.hull

AUTHORS¶

James Darrell McCauley, Purdue University GRASS 5 update, improvements: Andrea Aime, Modena, Italy GRASS 5.7 update: Radim Blazek Last changed: $Date: 2013-03-26 22:18:02 +0100 (Tue, 26 Mar 2013) $ Full index © 2003-2014 GRASS Development Team