Displaying 20 results from an estimated 1000 matches similar to: "Package ``deldir'' available from CRAN."
2006 Jul 19
2
voronoi tessellations
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)
plot(x,y,col='blue')
when
2007 Nov 27
1
voronoi/Delaunay/Dirichlet tessellation on sphere in R or S?
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,
2018 Jan 25
0
Geometry delaunayn and deldir results, differing results from Octave due to decimal precision?
I just looked at the data at the URL you posted and it looks like it
consists
of all the points in a rectangular grid. When you triangulate a rectangle
it is
arbitrary whether you use the SW-NE or the SE-NW diagonal and that looks
like the only difference between the various algorithms.
Bill Dunlap
TIBCO Software
wdunlap tibco.com
On Thu, Jan 25, 2018 at 5:14 AM, Yuen, Kam <k.yuen at
2011 Feb 24
1
weighted Voronoi diagrams
Dear R-users,
Does anyone know how to do weighted Voronoi diagrams (Dirichlet
tesselation) in R? To be more specific, I have a set of coordinates for
tree locations on a plot, and I'm looking for a way to do the
tesselation so that the polygon size for each tree depends on the size
of the subject tree, and the size of its neighbors. So, the location of
the bisection between two trees
2004 Aug 31
0
N-dimensional delaunay tesselation & voronoi diagrams
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
packages that do this (maybe by calling
2018 Jan 24
0
Geometry delaunayn and deldir results, differing results from Octave due to decimal precision?
"The question is, what is making the results for the R packages different
from each other?"
There are literally thousands of R packages, contributed independently by
thousands of people. There should be no expectation of consistency or for
that matter, "correctness", among them. Caveat emptor.
Only within the base R distribution, maintained and mostly written by the R
Core
2006 Apr 06
1
rounding of voronoi vertices using deldir()
Hello list,
I'm just getting started with using R - I have been trying over the past
day or so to work out a method for generating voronoi polygons for
PostGIS using SQL. I was able to put together a procedure which works
relatively well, but is somewhat inefficient. Someone on the PostGIS
list pointed me to the deldir() function in R, for which I can export a
text file with x/y coordinates
2018 Jan 24
4
Geometry delaunayn and deldir results, differing results from Octave due to decimal precision?
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
2001 Apr 14
0
How to create polygons from voronoi objects in tripack?
Hello.
I'd like to convert voronois object created by tripack to polygons to use
them in GIS(Geographic Information Systems) software. I tried to create
voronoi objects by using following code.
> 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
2007 Aug 27
0
Monmonier algorithm
Hello,
Here is a late answer, but an answer nonetheless to the question I asked
almost one year ago on this list:
> On Wed, 29 Mar 2006, Thibaut Jombart wrote:
>> Hello list,
<http://tolstoy.newcastle.edu.au/R/help/06/03/24318.html#24322qlink1>
/>> /
/>> does anyone know if Monmonier algorithm is available in R? I've
checked /
/>> several spatial
2012 Sep 24
0
Deldir() Thiessen Polygons Problem
Good evening to all.
I find myself trying to create some Thiessen Polygons, in order to finish a
meteorology research.
This is the script I found to create the Polygons:
*
*
*voronoipolygons <- function(x) {*
* require(deldir)*
* if (.hasSlot(x, 'coords')) {*
* crds <- x@coords *
* } else crds <- x*
* z <- deldir(crds[,1], crds[,2])*
* w <- tile.list(z)*
* polys
2004 Jun 01
0
qhull in R?
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
1998 Dec 04
1
contour labelling [was "Re: image ()"]
> From: Bill Simpson <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
2012 Jul 26
2
precision warning in delaunayn function
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,
+ 621879,7071762,
+
2010 Oct 15
0
tessellation from biological data in spatstat
Hi,
I'm new to this mailing list so apologies if this is too basic. I have
confocal images 512x512 from which I have extracted x,y positions of the
coordiates of labelled cells exported from ImageJ as a.csv file. I also
have images that define an underlying pattern in the tissue defined as
areas of different pixel values 0 or 255 (also 512x512) I've exported
these images as .txt
2005 Nov 13
4
voronoi
Is there any pure r code to do delaunay or voronoi diagrams?
Thanks!
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2012 Jul 18
1
convert deldir$delsgs to a X3D IndexedTriangleSet
Anyone knows how to convert a deldir$delsgs to a X3D IndexedTriangleSet?
Are there already any functions/packages?
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2008 Feb 07
1
Voronoi
Hello everyone
I have a problem with tripack package, I want to perform a Voronoi
tessellation on a specific domain (I have the shape file), in order to
weight my climatic data with the area ... How Can I do it?
Thank you very much
Andrea
2003 Aug 14
1
Contouring irregular xyz data via TIN
Dear,
I have XYZ data available in a MySQL database. I get it out, can plot
the data with the plot() function, load it into a geoR datastructure.
But what I actually would like to do is a simple contouring 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
2006 Apr 18
0
scalassoc package
Many new things at
http://www.cuddyvalley.org/psychoR/
The scalassoc package, which fits exponential distance association
models
to indicator matrices, it now at version 1.0.0. It seems to be robust
and
can analyze large examples easily. It is a major improvement (in
speed and
robustness) over the distassoc package, which is at the same site.
scalassoc does something neat (if you like