search for: hull

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 <- matrix(c(...

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, Charlottes...

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

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 u...

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 my data. Is there some other type of "chull" function that will allo...

Hi there dear R users! Anyone knows why does matchit function returns error whenever the "hull" option is used (either "hull.both", "hull.control" or "hull.treat"). Things work well with all the rest of discard options. This is the error msg. >m.out.base <- matchit(formula=f, data=d, method=m, discard="hull.control") [1] "Preprocessin...

...f 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 data points which define the tips of my neurons. I have found the R function chull which finds a 2D convex hull, but not have found any 3D routines. I wondered if there were any packages / publicly available code I could use. Having found the convex hull, it would be handy if t...

Hi guys I have data that contains the variances vt of the yields of 1, 2, 3, 4, 5,10, 20 year bonds. Assuming the Hull-White model for the yield of a t-year zero-coupon bond, I have to estimate the ? of the Hull-White model using nonlinear least squares and give a 95% con?dence interval for each parameter. Please can you guys tell how to find out ? using R. Any suggestion regarding what functions to use etc would b...

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.c...

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 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 ca...

...hin the Fields package) for a while now to interpolate different sedimentary units. Due to the method of formation of the units I know that at some edges the thickness of the unit decreases to zero. I was wondering if there was someway to specify that the interpolation only occurs within the convex hull of the data, outside of which the the values are zero. I am having problems with the output surface 'curling' up at distance from the data. Thanks, Sam -- View this message in context: http://r.789695.n4.nabble.com/Applying-interpolation-within-a-convex-hull-tp3454690p3454690.html Sent f...

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 32...

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 am running the following code (testing the use of the simplex function to determine if a point is in the convex hull of another set of points or not): >a <- c(0, 0) >A3 <-matrix(c(1,2,3,4,1,1), ncol = 2, byrow = T) >b3 <-c(1.5, 3.5, 1) >simplex(a = a, A3 = A3, b3 = b3) and the following error message appears: Error in simplex1(out1$a[1:(n + m1 + m2)], out1$A[, 1:(n + m1 + m2)], :...

....fm.cv_vertscrollbar set" scrollbar $base.fm.cv_vertscrollbar -orient vertical \ -command "$base.fm.cv yview" pack $base.fm.cv -side left -fill both -expand true pack $base.fm.cv_vertscrollbar -side right -fill y pack $base.fm -side top -fill both -expand true set hull [frame $base.fm.cv.hull -borderwidth 2 -relief ridge] set wid [winfo width $base.fm] $base.fm.cv create window 0 0 -anchor nw -window $hull -width 10 -height 500 -tag window bind $base.fm.cv <Configure> "ResizeCanvas %W %w %h" return $hull } I have successfully transl...

Ranjan Maitra writes: > Does anyone have a suggestion (or better still) code for sampling > from the uniform distribution over the convex hull of a set of > points? This is implemented in library 'spatstat'. If x and y are vectors of coordinates of your initial set of points, library(spatstat) W <- convexhull.xy(x, y) P <- runifpoint(42, W) will compute the convex hull and generate 42 independent unifor...

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...

...requirement is that the host samba server be a member of the active directory. And the config mechanism uses "/usr/bin/ntlm_auth --helper-protocol=ntlm-server-1" The smb.conf file being used is [global] workgroup = security = domain password server = p.q.r.s realm = ADIR.HULL.AC.UK preferred master = no server string = Hull Comms support server security = ADS use spnego = yes encrypt passwords = yes log level = 3 log file = /var/log/samba/%m max log size = 50 winbind separator = + idmap uid = 10000-20000 idmap gid = 10000-20000 bind...

...started giving this same error before, while RSVGTipsDevice was still working two months ago). I would really appreciate any help with this matter. Best regards, Leandro -- ############################################################### Leandro R. Monteiro Department of Biological Sciences and Hull York Medical School The University of Hull Hull, HU6 7RX, United Kingdom Tel: 44 1482-462077 E-mail: L.Monteiro at hull.ac.uk http://sites.google.com/site/morphogroup/ ############################################################### -------------- next part -------------- An embedded and charset-uns...