1v.voronoi(1)                  Grass User's Manual                 v.voronoi(1)
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4

NAME

6       v.voronoi  - Create a Voronoi diagram from an input vector map contain‐
7       ing points or centroids.
8

KEYWORDS

10       vector
11

SYNOPSIS

13       v.voronoi
14       v.voronoi help
15       v.voronoi [-lt] input=name output=name  [--overwrite]
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17   Flags:
18       -l  Output tessellation as a graph (lines), not areas
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20       -t  Do not create attribute table
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22       --overwrite
23
24   Parameters:
25       input=name
26           Name of input vector map
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28       output=name
29           Name for output vector map
30

DESCRIPTION

32       v.voronoi uses an existing  vector  points  map  (input)  to  create  a
33       Voronoi diagram (Thiessen polygons) in a new vector map (output).
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35       Voronoi diagram and Delaunay triangulation example: | Delaunay Triangu‐
36       lation (left pane), Voronoi diagram  (center  pane),  and  both  (right
37       pane)
38

NOTES

40       Voronoi  diagrams may be used for nearest-neighbor flood filling.  Give
41       the centroids attributes (start with v.db.addcol), then optionally con‐
42       vert to a raster map with v.to.rast.
43

EXAMPLE

45       Commands used with the Spearfish dataset to create the above figure.
46         g.region n=4927250 s=4919400 w=588650 e=594850
47         d.frame -c fr=one at=0,100,0,33.3333
48         d.frame -c fr=two at=0,100,33.3333,66.6667
49         d.frame -c fr=three at=0,100,66.6667,100
50         v.delaunay -lr in=archsites out=arch_delaunay
51         d.frame -s one
52         d.vect arch_delaunay
53         d.vect archsites color=red fcolor=red size=5 icon=basic/circle
54         v.voronoi -l in=archsites out=arch_voronoi
55         d.frame -s two
56         d.vect arch_voronoi type=line
57         d.vect archsites color=red fcolor=red size=5 icon=basic/circle
58         d.frame -s three
59         d.vect arch_voronoi type=line
60         d.vect arch_delaunay color=blue
61         d.vect archsites color=red fcolor=red size=5 icon=basic/circle
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63

BUGS

65       Only attribute table of field 1 is copied.
66

REFERENCES

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

72        v.delaunay, v.hull,
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AUTHORS

75       James Darrell McCauley, Purdue University
76       GRASS 5 update, improvements: Andrea Aime, Modena, Italy
77       GRASS 5.7 update: Radim Blazek
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79       Last changed: $Date: 2006/05/24 08:51:52 $
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81       Full index
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85GRASS 6.2.2                                                       v.voronoi(1)
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