search for: ellipsoid

Hello, in a three dimensional coordinate system, I'd like to find all my experimental data points that fall within an ellipsoid around a fixed coordinate. The fixed point is defined by (x.coord.point, y.coord.point, z.coord.point). The coordinates of the ellipsoid are given by the three vectors x,y,z. In a previous version of my code, I simply used a box instead of an ellipsoid to sort my data, which was really easy as...

+ Hello, The parametric equations of an ellipsoid can be written in terms of spherical coordinates. The three spherical coordinates are converted to Cartesian coordinates by X=a cos (α) sin(θ) Y=b sin(α) sin(θ) Z=c cos(θ) for α and θ The parameter α varies from 0 to 2 π and θ varies from 0 to π . Here ( X o , Y o ,Z o ) is the cen...

Dear list, I'm trying to visualise some ellipsoidal shapes in 3D. Their position, axes, and angular orientation can be arbitrary. I saw an ellipse3d function in rgl; however it is heavily oriented towards the statistical concept of ellipse of confidence, whilst I am just concerned with the geometrical object. Below is my current implementation. I...

I have a 3xN matrix of parameters obtained from N regressions where the 3 parameters are jointly statistically significant. I would like to reproduce a 3D confidence ellipsoid projecting 2D ellipses onto the XY plane as in Figure 5.2 in this text<http://books.google.com/books?id=PMeJGeXA09EC&pg=PA172&dq=confidence+ellipsoid&hl=en&sa=X&ei=oWQxT4OgBYLSiALW85WtAw&ved=0CEIQ6AEwAg#v=onepage&q=confidence%20ellipsoid&f=false> . Is this pos...

Hey, all I am going to plot several 3-dimensional ellipsoids in R. For example, A is such a ellipsoid with mean u=[1 1 1]', covariance matrix C=[1 0 .5;0 1 .6;.5 .6 1]; So how can I plot such object in 3D space? Is there some function to achieve this? Thanks. Fred

Dear all, Has anyone written functions to compute (and ideally project / plot onto a plane) confidence ellipsoids for q linear model parameters, q > 2 ? Greetings and best wishes, Renaud -- Dr Renaud Lancelot, v?t?rinaire CIRAD, D?partement Elevage et M?decine V?t?rinaire (CIRAD-Emvt) Programme Productions Animales http://www.cirad.fr/presentation/programmes/prod-ani.shtml ISRA-LNERV...

Hi all, Can anyone please guide me how to draw a Concentration ellipsoid for a bivariate system with a bivariate normal dist. having a VCV matrix : Sigma <- matrix(c(1,2,2,5), 2, 2) I would like to draw in using GGPLOT. Your help will be highly appreciated. Thanks, -- View this message in context: http://www.nabble.com/Concentration-ellipsoid-tp25315705p25315705...

John Fox wrote: >The confidence ellipse for a pair of coefficients is just (with an >adjustment for size) the perpendicular shadow of the joint ellipsoid, in >the same sense that the confidence intervals for individual coefficients >are shadows of the joint ellipsoid or ellipse. The usual confidence ellipse >for 2 of q coefficients uses qf(.95, 2, df.error) to scale the ellipse; if >you want to scale the ellipse as a literal shadow of th...

Dear list, I've generated a list of 3D coordinates representing ellipsoids in arbitrary orientations. I'm now trying to obtain a 2D projection of the scene, that is to draw the silhouette of each object on a plane (x,y). The only way I could think of is to compute the convex hull of the (x,y) coordinates of each object and use this as the outline of the obj...

...a tool that offers exceptionally useful visualizations. As an example, the options to run this function as follows is very much what I'm after but with a categorical response instead of a continuous one library(car) library(rgl) scatter3d(prestige ~ income + education | type , surface=FALSE, ellipsoid=TRUE, revolutions=3, data=Duncan) Using my data I'd like to use the function as follows: scatter3d(CSSS$VegtypeID ~ CSSS$MeanAnnualDepth + CSSS$Hydroperiod + CSSS$MedianWet, ellipsoid=TRUE, revolutions=3, data=CSSS) or: scatter3d(CSSS$DA7Depth ~ CSSS$MeanAnnualDepth + CSSS$Hydroperiod + CSS...

Dear All, The Minimum Volume Ellipsoid estimator ("cov.mve") was part of S+ but I cannot find it in R. Where can I find it? Why was it excluded? Cheers, Patrik Sweden

I am interested in making a random sample from a uniform distribution of points over the surface of the earth, using the WGS84 ellipsoid as a model for the earth. I know how to do this for a sphere, but would like to do better. I can supply random numbers, want latitude longitude pairs out. Can anyone point me at a solution? Thanks very much. -- Russell Senior ``I have nine fingers; you have ten.'' seniorr at...

...support for the analysis. As far as I can determine, scatter3d does not save the output of the routine as an object so I can not x <- scatter3d(MADep2010 ~ Day7Max2010 + S7DryFreq2010 | as.factor(VegClass), data = Veg , axis.scale = TRUE, sphere.size=1.5, surface=FALSE, parallel=FALSE, ellipsoid=TRUE, revolutions=1, surface.col =c("red", "green", "blue", "gold", "magenta")) str(x) NULL I would like to extend the work by calculating the percent of overlapping area among the ellipsoides on a community by community basis. Can anyone...

...horizontal cylinder preferably in RGL device (because this gives the look from different angles). Basic idea is from http://www.tau.ac.il/cc/pages/docs/sas8/insight/chap18/sect3.htm. Below is the description exactly what I want to do. Please see at figure 18.6, 1st plot. Here it is an confidence ellipsoid. Suppose now you put another 4 same ellipsoids on top of each. Therefore you would get a cylinder type 3-D picture vertically. I do not need to plot indiv. points rather just ellipsoids. Also another vertical line which goes through the mid-points (i.e. expectation of corresponding BVN). Same thin...

I am curious if there is code developed to plot confidence regions in 3D. The scatterplot3d function generates the plot I want, but would like an 3D equivalent to the data.ellipse function. Any help in this direction would be appreciated, be it theoretical, graphical, or otherwise. Melanie Edwards Senior Statistician Exponent 15375 SE 30th PL, Suite 250 Bellevue, WA 98007 Tel: (425) 519-8714

Hi all, How do I visualize a contour of a tri-variate normal distribution? I just like to see the ellipsoid very much. I hope there is a easy way or existing method in R. Thank you a lot! Michael. [[alternative HTML version deleted]]

For a paper dealing with generalized ellipsoids, I want to illustrate in 3D an ellipsoid that is unbounded in one dimension, having the shape of an infinite cylinder along, say, z, but whose cross-section in (x,y) is an ellipse, say, given by the 2x2 matrix cov(x,y). I've looked at rgl:::cylinder3d, but don't see any way to make it...

Hi all, I would like to know a way of calculating the distance between 2 points when I already have the longitude and latitude of the points. For example : Point 1 : 52? 9'54.00"N 4?25'8.40"E Point 2 : 52?27'46.80"N 4?33'18.00"E Distance between point 1 and point in km .... Is there any functions already available for this ? Any help will be much

Dear all, I write to the community to know if other people expierenced the same problem. I want to save a rgl scene where I plotted a 3d cloud of spheres whose radius is set proportional to a given variable and coloured by another group variable and with 95% ellipsoids for distribution of any group. I had no problem at all for coding but I had two problem when saving the scene (in any format) using rgl.postscript() 1- using plot3d(), if the points are set to sphere whose radius is proportional to a given variable the rgl.postscript() causes R crash 2- using si...

Hi, does anyone know how to plot 3D parametric surface,e.g ellipsoid: x=a*cos(s)*cos(t), y=b*sin(s)*cos(t), z=sin(t); s in [0,2*pi], t in [-pi,pi]. Vytautas Maniusis, Vilnius University, Lithuania