On Tue, 2007-07-31 at 11:21 +0100, Wilson, Andrew wrote: > Probably a very simple query: > > When I try to plot a curve from a fitted polynomial, it comes out rather > jagged, not smooth like fitted curves in other stats software. Is there > a way of getting a smooth curve in R? > > What I'm doing at the moment (for the sake of example) is: > > > x <- c(1,2,3,4,5,6,7,8,9,10) > > > y <- c(10,9,8,7,6,6.5,7,8,9,10) > > > b <- data.frame(cbind(x,y)) > > > w <- gls(y ~ I(x)+I(x^2),correlation=corARMA(p=1),method="ML",data=b) > > > plot(predict(w),type="l")
replace the line above with the following: pred.dat <- data.frame(x = seq(min(x), max(x), length.out = 100)) plot(predict(w, pred.dat), type = "l") The general idea is to produce predictions over the range of x, so we produce a new data frame with component x, that contains 100 values from min(x) to max(x). We then get predicted values for each of these new values of the predictor in pred.dat, and plot them Increase/decrease length.out to get something suitably smooth without sending your computer into meltdown. HTH G > > Many thanks, > > Andrew Wilson > > ______________________________________________ > 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 > and provide commented, minimal, self-contained, reproducible code. -- %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% Gavin Simpson [t] +44 (0)20 7679 0522 ECRC, UCL Geography, [f] +44 (0)20 7679 0565 Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ UK. WC1E 6BT. [w] http://www.freshwaters.org.uk %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.
