For another approach you might want to look at Predict.Plot and TkPredict from the TeachingDemos package. The code from those could be adapted to do 3d plots.
-- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of Joshua Wiley > Sent: Monday, October 11, 2010 3:03 PM > To: r-help@r-project.org > Subject: Re: [R] Is there a regression surface demo? > > Thanks for everyone's responses. Just to follow up, here is a working > version of my original. The code is not pretty, but it functions. > Assuming you have the 'rgl' package installed and have sourced this > function, here are some examples: > > RegSurfaceDemo(mpg ~ vs + wt, data = mtcars) > RegSurfaceDemo(mpg ~ vs * wt, data = mtcars) > RegSurfaceDemo(qsec ~ disp * hp, data = mtcars) > > It cannot handle factors, and the axes labels are hideous...I'll get > to that eventually. > > Thanks for all your help and suggestions. > > Josh > > RegSurfaceDemo <- function(formula, data, xlim = NULL, ylim = NULL, > zlim = NULL, resolution = 10) { > require(rgl) > ## This cannot be the proper way to extract variable names from > formula > vars <- rownames(attr(terms(formula), "factors")) > > ## if no limits set, make them nearest integer to > ## .75 the lowest value and 1.25 the highest > ranger <- function(x) { > as.integer(range(x) * c(.75, 1.25)) > } > if(is.null(xlim)) {xlim <- ranger(data[, vars[2]])} > if(is.null(ylim)) {ylim <- ranger(data[, vars[3]])} > if(is.null(zlim)) {zlim <- ranger(data[, vars[1]])} > > ## This does not actually work because the data frame > ## does not get named properly (actually it throws an error) > f <- function (x, y) { > newdat <- data.frame(x, y) > colnames(newdat) <- c(vars[2], vars[3]) > predict(my.model, newdata = newdat) > } > > ## Fit model > my.model <- lm(formula = formula, data = data) > > ## Create X, Y, and Z grids > X <- seq(from = xlim[1], to = xlim[2], length.out = resolution) > Y <- seq(from = ylim[1], to = ylim[2], length.out = resolution) > Z <- outer(X, Y, f) > > ## Create 3d scatter plot and add the regression surface > open3d() > with(data = data, > plot3d(x = get(vars[2]), y = get(vars[3]), z = get(vars[1]), > xlim = xlim, ylim = ylim, zlim = zlim)) > par3d(ignoreExtent = TRUE) > surface3d(X, Y, Z, col = "blue", alpha = .6) > par3d(ignoreExtent = FALSE) > return(summary(my.model)) > } > > > > On Mon, Oct 11, 2010 at 1:28 PM, Ista Zahn <iz...@psych.rochester.edu> > wrote: > > There is also wireframe() in lattice and bplot in rms. > > > > -Ista > > > > On Mon, Oct 11, 2010 at 3:49 PM, G. Jay Kerns <gke...@ysu.edu> wrote: > >> Dear Josh, > >> > >> On Mon, Oct 11, 2010 at 3:15 PM, Joshua Wiley > <jwiley.ps...@gmail.com> wrote: > >>> Hi All, > >>> > >>> Does anyone know of a function to plot a regression surface for two > >>> predictors? RSiteSearch()s and findFn()s have not turned up what I > >>> was looking for. I was thinking something along the lines of: > >>> http://mallit.fr.umn.edu/fr5218/reg_refresh/images/fig9.gif > >>> > >>> I like the rgl package because showing it from different angles is > >>> nice for demonstrations. I started to write my own, but it has > some > >>> issues (non functioning code start below), and I figured before I > >>> tried to work out the kinks, I would ask for the list's feedback. > >>> > >>> Any comments or suggestions (about functions or preferred idioms > for > >>> what I tried below, or...) are greatly appreciated. > >>> > >>> Josh > >>> > >> > >> [snip] > >> > >> I haven't tried to debug your code, but wanted to mention that the > >> Rcmdr:::scatter3d function does 3-d scatterplots (with the rgl > >> package) and adds a regression surface, one of 4 or 5 different > types. > >> If nothing else, it might be a good place to start for making your > >> own. > >> > >> A person can play around with the different types in the Rcmdr under > >> the Graphs menu. Or, from the command line: > >> > >> library(Rcmdr) > >> with(rock, scatter3d(area, peri, shape)) > >> > >> I hope that this helps, > >> Jay > >> > >> ______________________________________________ > >> R-help@r-project.org mailing list > >> https://stat.ethz.ch/mailman/listinfo/r-help > >> PLEASE do read the posting guide http://www.R-project.org/posting- > guide.html > >> and provide commented, minimal, self-contained, reproducible code. > >> > > > > > > > > -- > > Ista Zahn > > Graduate student > > University of Rochester > > Department of Clinical and Social Psychology > > http://yourpsyche.org > > > > > > -- > Joshua Wiley > Ph.D. Student, Health Psychology > University of California, Los Angeles > http://www.joshuawiley.com/ > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting- > guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
