a strategy for this that I use is just persp(interp(x,y,z))
where interp is from the Akima package, and x,y,z are all of the same length. url: www.econ.uiuc.edu/~roger Roger Koenker email [EMAIL PROTECTED] Department of Economics vox: 217-333-4558 University of Illinois fax: 217-244-6678 Champaign, IL 61820 On Feb 13, 2006, at 3:07 PM, Denis Chabot wrote: > Hi, > > This is probably documented, but I cannot find the right words or > expression for a search. My attempts failed. > > I have a data frame of 3 vectors (x, y and z) and would like to > transform this so that I could use persp. Presently I have y-level > copies of each x level, and a z value for each x-y pair. I need 2 > columns giving the possible levels of x and y, and then a > transformation of z from a long vector into a matrix of x-level rows > and y-level columns. How do I accomplish this? > > In this example, I made a set of x and y values to get predictions > from a GAM, then combined them with the predictions into a data > frame. This is the one I'd like to transform as described above: > > My.data <- expand.grid(Depth=seq(40,220, 20), Temp=seq(-1, 6, 0.5)) > predgam <- predict.gam(dxt.gam, My.data, type="response") > pred.data <- data.frame(My.data, predgam) > > pred.data has 150 lines and 3 columns. > > Thanks for your help, > > Denis Chabot > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting- > guide.html ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html