search for: delaunay

There's Renka's STRIPACK, and TRIPACK, respectively, ACM TOMS Algorithms 772 and 751, and there's the R package "deldir" which does the Delaunay for a plane, but does anyone have or know of the tessellation in R for a sphere? Also, is there a standard indexing scheme for Delaunay facets, and perhaps of edges in such facets? I'd expect that to be a publication reference, or even textbook. TIA, - Jan [[alternative HTML version de...

The problem: I would like to translate the Octave algorithm in griddata.m to R. Within the griddata algorithm calls are made to the Delaunay function. For the R translation I have found delaunayn within the "geometry" package and also the deldir package. Both do similar things but give slightly different results depending on the input. The question is, what is making the results for the R packages different from each other? An...

Hi, I've been looking for functions that can do delaunay tesselation and generate voronoi cells. I came across deldir and tripack but both seem to be restricted to 2D points. Are there any packages that can do a tesselation in N dimensions? I know that Matlab and Mathematica use the qhull package to provide functions for this. Does anybody know of any R...

...pus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Wed, Jan 24, 2018 at 5:59 AM, Yuen, Kam <k.yuen at fugro.com> wrote: > The problem: > I would like to translate the Octave algorithm in griddata.m to R. > Within the griddata algorithm calls are made to the Delaunay function. For > the R translation I have found delaunayn within the "geometry" package and > also the deldir package. > Both do similar things but give slightly different results depending on > the input. > The question is, what is making the results for the R packages diff...

...gt; output. > > > > Regards, > > > > Kam > > > > > > *From:* William Dunlap [mailto:wdunlap at tibco.com] > *Sent:* 24 January 2018 19:29 > *To:* Yuen, Kam <k.yuen at fugro.com> > *Cc:* r-help at r-project.org > *Subject:* Re: [R] Geometry delaunayn and deldir results, differing > results from Octave due to decimal precision? > > > > All three results give the same collection of triangles. They > > don't all agree on whether the points in a triangle are in clockwise > > or counterclockwise order. If the orient...

Dear R helpers, I try to use the 'delaunayn' function in the 'geometry' package for Delaunay triangulation in 2 dimensions. For the four following points, I get a warning message : > coord=matrix(ncol=2,byrow=TRUE,c(622633,7073452, + 621228,7073517, + 62187...

A package for calculating and plotting the Delaunay triangulation and the Dirichlet/Voronoi tessellation, of a planar set of points, is now available from CRAN. The package is called ``deldir''. The package consists of a port from Splus to R of a library section which has been available for some time from the Splus software segment of stat...

...touring of the data based on a no Kriging interpolation such as TIN based. I know the first thing I shold do is interpolate a full matrix for the region I have my points for, then contour should do its work. Any idea which function can be used for XYZ interpolations, maybe/hopefully based on a Delaunay triangulation in combination with linear or spline interpolation. Is there a package that allows me to do this? Kris -- ------------------------------------------------------------------------ http://perswww.kuleuven.ac.be/~u0027178/VCard/mycard.php?name=krisn http://gloveg.kuleuven.ac.be...

Hi, does anyone know if there is an implementation of qhull (http://www.qhull.org/) in R? anyone is planning on it? "Qhull computes convex hulls, Delaunay triangulations, halfspace intersections about a point, Voronoi diagrams, furthest-site Delaunay triangulations, and furthest-site Voronoi diagrams. It runs in 2-d, 3-d, 4-d, and higher dimensions. It implements the Quickhull algorithm for computing the convex hull. Qhull handles roundoff errors...

Is there any pure r code to do delaunay or voronoi diagrams? Thanks! --------------------------------- [[alternative HTML version deleted]]

...de. > library(tripack) > x <- rnorm(10) > y <- rnorm(10) > plot(x,y) > v<-voronoi.mosaic(x,y) > plot(v) But from here, I could not create polygons. Of course, I know v$n1..3 -- node info, v$x and v$y coordinates. But I only create lines from them. For triangulation(Delaunay) object, there is trinagle object form which I can create polygon. But for Voronoi, there's no polygon object which has constructed "Voronoi" polygons. Does anyone know how to do this solution? -------------- next part -------------- An HTML attachment was scrubbed... URL: https://...

...to genetic data analysis, these functions can handle other kind of data as well. The main difference I can see between this implementation and the original algorithm is that here, the function uses objects connected on a neighbouring graph rather than polygons of a Voronoi tesselation. Thus, Delaunay triangulation shall be used to recover the original version of the algorithm, but other graphs are also possible (e.g. Gabriel's graph). Regards, Thibaut. -- ###################################### Thibaut JOMBART CNRS UMR 5558 - Laboratoire de Biom?trie et Biologie Evolutive Universite Ly...

...<wsimpson at uwinnipeg.ca> > Subject: Re: contour labelling [was "Re: [R] image ()"] > MIME-Version: 1.0 > > > We may be missing the crux here: was it to have a means of > > displaying such surfaces? > > Yes, bang on. I knew of the > existence of the Delaunay code in the R libraries. Yes I want > to make a picture that places a planar facet on each triangle. > The resulting surface looks like the surface of a cut diamond > for example (assuming the cuts give triangular facets). So far > as I know there is no way to display such a 3D plot in...

Hello, I'd like to make a z(x,y) plot for irregularly spaced x,y. What are routines are available in R for this purpose? Thanks, Mark

Hello all, I'm attempting to conduct spatial analysis of trees within a plot. I want to see if the trees are spatially correlated to soil characteristics, say pH, or moisture content. I think one way to do it is with mpl, however, my soil characteristics were not taken at exactly the same locations as my trees and further, the vectors aren't the same length. I'm getting the

> From: Martin Maechler <maechler at stat.math.ethz.ch> > To: royle at bearmtn-e0.cgd.ucar.edu > CC: lgygax at access.unizh.ch, r-help at stat.math.ethz.ch > Subject: contour labelling [was "Re: [R] image ()"] > Mime-Version: 1.0 (generated by tm-edit 7.106) > > >>>>> "Jeffrey" == Jeffrey A Royle <royle at bearmtn-e0.cgd.ucar.edu>

...ii:dimension){ > matDistances[ii,jj]<- norm( df[,ii] - df[,jj]) > } > } This is both inefficient and ugly, I'll welcome any suggestion. In particular: - the location of the points on the sphere is not ideal (understand: not uniformly distributed over the area): i looked into delaunayn from the geometry package and qhull.com but at best I obtained a random set of points on the sphere. It must be a most classical problem ?? generating a uniform distribution of points on a sphere??, but i've set that problem aside for the moment. - the double for loop over all the poi...

Hello list! I have a problem with the function 'persp'. I have a data set with the variables X -> The X coordenate of the insect Y -> The Y coordenate of the insect deep-> how deep the insect buried into the soil. I would like to have a plot with a surface simulating the way the insect buried. Is it possible? If I type persp(x,y,deep) R gives me this error message Error in

Hi, I have collected data on trees from 5 forest plots located within the same landscape. Data within the plots are spatially autocorrelated (calculated using Moran's I). I would like to do a ANCOVA type of analysis combining these five plots, but the assumption that there is no autocorrelation in the residuals is obviously violated. Does anyone have any ideas how to incorporate these spatial