Re: [R] voronoi tessellations

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Wed 19 Jul 2006 - 17:15:51 EST

On Tue, 18 Jul 2006, Don MacQueen wrote:

> I'll suggest going to the CRAN packages page and doing a search for "voronoi".

The problem here is that `Voronoi tessellation' is a secondary name. The concept has many names, including Dirichlet tessellation and Thiessen polygons, and Dirichlet has priority over Voronoi.

> Also, search for 'triangulation', since that is one of the uses of them.

I know of packages deldir, tripack and perhaps geometry.

> -Don
>
> At 11:46 PM -0400 7/18/06, zubin wrote:
> >Hello, looking to draw a voronoi tessellations in R - can anyone
> >recommend a package that has tackled this?
> >
> >some background:
> >
> >i have a economic data set and created a sammons projection, like to now
> >overlay a voronoi tessellation over the sammons 2-D solution for a slick
> >visual, and potentially color each tessellation element based on a metric.
> >
> >home.u <- unique(home1)
> >home.dist <- dist(home.u)
> >home.sam <- sammon(home.dist,k=2)
> >plot(home.sam$points)

Wait a minute. If this is sammon() from MASS (uncredited), it is not a projection, and there is no relevant concept of distance between points in the mapped space apart from between the supplied points.

I suggest Zubin reads carefully the reference whose support software he appears to be using. (It would also have answered his question.)

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Wed Jul 19 17:26:59 2006

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