On 7/19/2006 4:21 PM, [EMAIL PROTECTED] wrote: > Okay, been working with tripack, seems the most mature package for this. Got > it to work well with their test data set - data(tritest). When i tried > random numbers to explore further, i am getting some results that don't > reconcile. > > example run this: > > library(tripack) > y <- runif(100) > x <- runif(100) > vm <- voronoi.mosaic(x,y) > plot(vm) > par(new=T)
Don't do that! That throws away the coordinate system that has already been established. Do it this way: library(tripack) y <- runif(100) x <- runif(100) vm <- voronoi.mosaic(x,y) plot(vm) points(x,y,col='blue') and if you want the axes, axis(1) axis(2) box() Duncan Murdoch > plot(x,y,col='blue') > > when you look at the plot of the mosaic overlayed with the raw data, the > mosaic should have each data point in 1 cell, however that is not the case - > any help would be appreciated. > > However if you run > > data(tritest) > x <- tritest$x > y <- tritest$y > vm <- voronoi.mosaic(x,y) > plot(vm) > par(new=T) > plot(x,y,col='blue') > > it looks at it should. > > -zubin > > >> From: Prof Brian Ripley <[EMAIL PROTECTED]> >> Date: 2006/07/19 Wed AM 03:15:51 EDT >> To: Don MacQueen <[EMAIL PROTECTED]> >> CC: zubin <[EMAIL PROTECTED]>, [email protected] >> Subject: Re: [R] voronoi tessellations >> >> 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, [EMAIL PROTECTED] >> 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 >> > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
