NAME

s.voronoi - Uses a GRASS sites list to produce a Voronoi diagram
(GRASS Sites Program)

SYNOPSIS

s.voronoi [-aq] sites=name vect=name [labels=name]

DESCRIPTION

s.voronoi uses an existing sites list (sites) to create a Voronoi diagram (Thiessen polygons) in a binary vector file (vect).

OPTIONS

Parameters:

sites=name
Name of existing sites file.
vect=name
Name of the output file (binary vector file).
labels=name
no labels, generate a serial category number or keep category from input file
options: no,generate,keep
default: keep

Flags:

-a
Use all sites found in the named sites file, rather than limiting output to sites falling within the current geographic region.
-l
Attempt to use site descriptions (category labels) as categories and attribututes for the vector file. Sites must be in the (E|N|#n desc) format for this to work.
-q
Quiet. Cut out the chatter.
s.voronoi can be run either non-interactively or interactively. The program will be run non-interactively if the user specifies the name of an existing site list file and a name for a vect file, using the form s.voronoi [-alq] sites=name1 vect=name2 where name1 is the name of an existing site list file and name2 is the name of vector output file. Alternately, the user can simply type s.voronoi on the command line, without program arguments. In this case, the user will be prompted for parameter values using the standard GRASS parser interface described in the manual entry for parser. In either case, v.spag and v.support should be run on the output (running v.spag is necessary so that nodes are created where the polygons cross the boundary of the region).

EXAMPLES

REFERENCES

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

SEE ALSO

v.autocorr, v.spag, v.support, s.delaunay, s.sweep

AUTHOR

James Darrell McCauley, Purdue University
GRASS 5 update, improvements: Andrea Aime, Modena, Italy