similar to: estimating volume from xyz points

Hi All, convhulln {geometry} computes the convex hull of a set of points in n- dimensions via .call, returning the hull itself, and also "unavoidably generates a diagnostic report on an Rterm console." See the example below. I need to access the results of the diagnostic report (specifically the computed hull volume) from within R, but I cannot see how. I've looked at

Hi, I seek to identify those points in/outside a multidimensional convex hull (geometry::convhulln). Any suggestions? Background just in case I'm going down a really wrong road: Given an observed data set with one dependent/observed variable (Y) and multiple (3 to 10) independent/design variables (X1, X2, ...) I want to increase the number of points by interpolating. I'm using

Dear all, I have a question about FD package. I?m trying to calculate functional diversity indices using insect data. My trait data includes dispersal ability (0, 0.5, 1), body size (continuous) and five feeding guilds coded as in percentages (for example; 0,0,0.5,0.5,0) since some of the species can have two different feeding guilds. However, the package only calculates when I run ?calc.Frich=

Dear R gurus and users, I seem to have problem finding the right tool for plotting convex hulls over 2D plots, after a cluster analysis. In fact I would like to draw a convex hull in 2D for a generic group of points. I found a "convhulln", but this doesn't seem to give me a convex hull. Here is what I do: > library(mvtnorm) > Mean <- c(2,1) > Sigma <-

Dear UseRs, I would like to know which function is the most efficient in finding convex hull of points in 3(or 2)-dimensional case? Functions for finding convex hull is the following: convex.hull (tripack), chull (grDevices), in.chull (sgeostat), convhulln (geometry), convexhull.xy (spatstat), calcConvexHull (PBSmapping). I also would like to know if there is a function that can be used

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

Dear all, I know that it is a know issue, but I would like to change the type of font on my plot, and I am not sure the rigth way. I would like to use Times New Roman font, but according to the "par()" help, some device allow we choose an family of fonts. I tryed par(family="times") without success. Surfing on R archieve I got an suggestion of use par(font.lab=6), but when I

Dear all, I have a data.frame like the sample below, and I would like to expand my data.frame using "population" variable. So, for each line of my data.frame I would like that the new data.frame have many rows as the population collumn. place<-c("place1", "place2", "place3", "place4", "place5") population<-c(100,200,300,50,30)

Dear all, I have strong interest on Ecological Niche Model, which in general use a set of environmental variables (continuous, categorical etc) and Presence (or Presense/Absence) records for species. I think that "grasp" and "adehabitat" packages could help me on these tasks. My input layers are on ASC format, and the record of species is a data-frame with X, Y, name of

Before coding this in C, I wanted to test the idea out in R. But I'm unsure if the theory is well-founded. I have a (user-supplied) black-box function which takes R^n -> R^3 and a defined domain for each of the input reals. I want to send some samples through the box to determine an approximation of the convex hull of the function's range. (I'll use the library from

Dear R, I have a covariates matrix with 10 observations, e.g. > X <- matrix(rnorm(50), 10, 5) > X [,1] [,2] [,3] [,4] [,5] [1,] 0.24857135 0.30880745 -1.44118657 1.10229027 1.0526010 [2,] 1.24316806 0.36275370 -0.40096866 -0.24387888 -1.5324384 [3,] -0.33504014 0.42996246 0.03902479 -0.84778875 -2.4754644 [4,] 0.06710229 1.01950917

I maintain the geometry package, which integrates the Qhull C library (http://qhull.org) into R. The Qhull function I hook into requires an open FILE handle as one of its arguments. I had set this file handle to stdout, but now R check NOTEs the presence of stdout, and the CRAN maintainers asked me to get rid of these NOTEs. Including the following defines means the checks are passed on CRAN:

Dear friends, Do you know how to calculate the CONCAVE hull of a set of points (2- dimensional or n-dimensional)? is that possible in R? (With a "smoothing" parameter of course). Best, -- Corrado Topi Global Climate Change & Biodiversity Indicators Area 18,Department of Biology University of York, York, YO10 5YW, UK Phone: + 44 (0) 1904 328645, E-mail: ct529 at york.ac.uk

You may use the "geometry" package and the "convhulln" function. This will allow you to compute the convex hull volume of a set of points in a n-dimensional space. -- Guilhaumon Fran?ois Laboratoire "Ecosyst?mes Lagunaires" UMR 5119 cc 93 Bat 24 Universit? Montpellier II 34 095 Montpellier France http://www.ecolag.univ-montp2.fr

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, +

Dear R-gurus, I know that it is not a R problem, but as need to implement some solution for this on R, I would like to know if someone help me on how to isolate X on the expression below. K=(sen A * sen B ) + ( cos A * cos B * cos ( X - Y ) ) Any help are welcome mitinho astronauta brazil [[alternative HTML version deleted]]

Does anyone know of a R package that will determine the convex hull of a high-dimensional dataset (say 4-10 dimensions). I know chull works for 2D data. I'm neophyte to R and convex hulls so please keep it simple. Many thanks Ben -- Ben Stapley. Biomolecular Sciences, UMIST, PO Box 88, Manchester M60 1QD. Tel 0161 200 5818 Fax 0161 236 0409

Hello, I have a distribution dataset for species consisting of xy coordinates at the 1km resolution, with only presence data. So a simplified example of a species distribution might be: y <- rbind(as.integer(rnorm(100,50,20)), as.integer(rnorm(200,100,30)), as.integer(rnorm(100,180,15))) x <- rbind(as.integer(rnorm(200,50,20)), as.integer(rnorm(200,100,20)), as.integer(rnorm(100,200,15)))

Hi everyone, I wonder if there is a code in r that can generate a 3d convex hull from a data-frame containing 3 columns and then use another database with the same three columns and for each row determine if the xyz point is inside or not the convex hull generated with the first database? The package geometry allows to calculate a hull and it's volume. I was planning to calculate the volume

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