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 14:18:02 -0700 (Tue, 26 Mar 2013) $

       Full index

       © 2003-2013 GRASS Development Team