similar to: convex-polygon in scatter plot

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

Dear list, Does anyone have a suggestion (or better still) code for sampling from the uniform distribution over the convex hull of a set of points? Many thanks and best wishes, Ranjan

Does anybody know if there are functions to: 1. Define a convex hull on a space with more than 2 dimensions? chull just works for a plane. 2. Numerically select elements within a given complex hull. Thanks! Dr. Agustin Lobo Instituto de Ciencias de la Tierra (CSIC) Lluis Sole Sabaris s/n 08028 Barcelona SPAIN tel 34 93409 5410 fax 34 93411 0012 alobo at ija.csic.es

Dear List Members, I'm presently carrying out morphological analysis of a data set of neuronal structures. These are essentially 3D binary trees. In due course I will be trying to use discriminant analysis or other methods to classify these neurons based on morphological variables such as total tree length, segment number etc. I would like to calculate a 3D convex hull for a set of X,Y,Z

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 <-

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

Hi there, I've been seeing this for quite a while now, but only today finally got off my lazy you-know-what and did a backtrace. Here's the requested info as per http://dovecot.org/bugreport.html: * Dovecot version [root at airframe]:~# dovecot --version 1.0.3 * Operating system or Linux distribution name Slackware 10.2, both kernel 2.6.21.3 and dovecot self-compiled * CPU

In R's maptools package, is there a built-in function to test if a given point is "inside" a given polygon on the map? The map was loaded from an ESRI Shapefile. The point's latitude and longitude are known. Thank you! Aleks -- ------------------------ Aleksandr Andreev Fulbright Fellow Graduate School of Management St Petersburg State University

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

Hi everyone, Using a simulation, I have to find what are the probabilities that, in a square region, the convex hull is a triangle, using the "chull" function. However, I have a hard time with the chull function, i did not see many examples in which the chull function is used. I searched a long time on google, but I did not find nothing. So, if anyone can help, Thanks!

I am modeling a trend surface using trmat and want to trim the resulting matrix to the area enclosed by my real data (i.e., remove all the extrapolated areas). I was using chull and in.chull to calculate the convex hull and change all the other values created by trmat to NA. However, my real data has portions that are slightly concave so chull would give me slivers that are extrapolations from

[Please CC me for all replies, since I am not currently subscribed to the list.] Hi all, I have the following problem/question: Imagine you have a two- dimensional plot, and you want to select a number of points, around which you could draw a polygon. The points of the polygon are defined by clicking in the graphics window (locator()/identify()), all points inside the polygon are

Dear all, Does anyone know of a function that calculates the area of the outer polygon constructed from a data frame with co-ordinates? For example, library(splancs) test = rbind(c(0,0), c(10,0),c(10,10),c(0,20)) plot(test) areapl(test) [1] 150 This is OK, but I want the same area to be returned (150) when adding yet another co-ordinate in the middle of the polygon: test = rbind(c(0,0),

Hello! Is there someone already working on an implementation of Splus' chull() function for R? If not, I would like volunteer to try it. For my "Diplom" I implemented convex peeling in C (some time ago), using an O(n log(n)) algorithm, so it probably will prove relatively easy to use that code for a R-function. Well, as least as easy as any programming tends to be. :-) Detlef

Dear Friends, Here is an algorithm for finding concave hulls: http://get.dsi.uminho.pt/local/ Has anyone implemented such an algorithm in R? RSiteSearch('concave hull') didn't reveal one (I think). _____________________________ Professor Michael Kubovy University of Virginia Department of Psychology Postal Address: P.O.Box 400400, Charlottesville, VA 22904-4400 Express Parcels

Sorry, I did not make my question clear. Since I have a point theme with many points, some of them may clump together. the problems here are: 1. how to find clumps in a point theme? 2. the convex-hull extension I found only deal with all the points in a theme at each time? how to make each convex hull around each point clump automatically? Thanks. Xiaohua On 5/12/06, Bob Booth <bbooth

I am using the Windows menu functions below which will work on the first pass, but if I repeat the same script I cannot get the WinMenuAddItem to work. This is a problem if I change the menu structure and reread the source code I am forced to quit and restart Rgui. "try.menu" <- function(){ OS <- .Platform$OS.type GUI <- .Platform$GUI if (!(OS == "windows" &

Hello, I got an error if I try to install a package. For example package emg: R CMD check emg Everything is fine. R CMD INSTALL emg I got the following errors: * installing to library 'c:/R_2_13_1/library' * installing *source* package 'emg' ... Error in file_path_as_absolute(dfile) : Datei './DESCRIPTION' existiert nicht ERROR: installing package DESCRIPTION failed fo

On Aug 12, 2019, at 8:54 PM, Thomas Zajic via dovecot <dovecot at dovecot.org> wrote: > > * Amir Caspi via dovecot, 12.08.19 22:01 > >> [~]# doveadm mailbox status -u cepheid firstsaved Junk >> Junk firstsaved=1563154976 >> >> I can't tell how that timestamp corresponds to a human-readable date, however. > > [zlatko at disclosure:~]$ date -d

Sorry, this is probably quite an easy question, but I'm new to R and couldn't find the answer anywhere. I'm using geoR and geoRglm, but can't figure out how to get a border in my geodata object. Does this need to be defined when I'm importing my data, or afterwards, and how do I go about doing this? Thanks -- View this message in context: